--- canonical: https://www.jkconcepts.at/en/web-technology-glossary/ robots: noindex, follow --- Web technology glossary # Web technologies: website terms explained What is DNS? How do a domain and hosting differ? What do API, SSR or Core Web Vitals mean? Here you’ll find web terms on two levels: easy to follow for getting started and technical for day-to-day practice. [Browse the terms](https://www.jkconcepts.at/en/web-technology-glossary/#glossar) [All knowledge areas](https://www.jkconcepts.at/en/knowledge/) At a glance ### Scope 80 terms ### Reading levels Simple and technical ### Last updated October 2026 From the browser to the backend ## Web technologies from A to Z Filter by topic or search for a specific question. Related terms guide you through frontend, backend, HTTP, CMS, performance and security. Search for a term or question Topic **80** terms shown Basics ## How websites work A quick introduction to domains, hosting, browsers, page structure and interfaces. [Website](https://www.jkconcepts.at/en/web-technology-glossary/#website) [Web App](https://www.jkconcepts.at/en/web-technology-glossary/#web-app) [Domain](https://www.jkconcepts.at/en/web-technology-glossary/#domain) [DNS](https://www.jkconcepts.at/en/web-technology-glossary/#dns) [Web Hosting](https://www.jkconcepts.at/en/web-technology-glossary/#webhosting) [Web Server](https://www.jkconcepts.at/en/web-technology-glossary/#webserver) [URL](https://www.jkconcepts.at/en/web-technology-glossary/#url) [HTTP](https://www.jkconcepts.at/en/web-technology-glossary/#http) [HTTPS](https://www.jkconcepts.at/en/web-technology-glossary/#https) [HTML](https://www.jkconcepts.at/en/web-technology-glossary/#html) [CSS](https://www.jkconcepts.at/en/web-technology-glossary/#css) [JavaScript](https://www.jkconcepts.at/en/web-technology-glossary/#javascript) [API](https://www.jkconcepts.at/en/web-technology-glossary/#api) Technical reference ### Architecture, APIs & performance Concepts for development, troubleshooting, operations and technical decisions. [REST API](https://www.jkconcepts.at/en/web-technology-glossary/#rest-api) [JSON](https://www.jkconcepts.at/en/web-technology-glossary/#json) [Webhook](https://www.jkconcepts.at/en/web-technology-glossary/#webhook) [SSG](https://www.jkconcepts.at/en/web-technology-glossary/#ssg) [SSR](https://www.jkconcepts.at/en/web-technology-glossary/#ssr) [CSR](https://www.jkconcepts.at/en/web-technology-glossary/#csr) [Hydration](https://www.jkconcepts.at/en/web-technology-glossary/#hydration) [Islands Architecture](https://www.jkconcepts.at/en/web-technology-glossary/#islands-architecture) [Cache-Control](https://www.jkconcepts.at/en/web-technology-glossary/#cache-control) [Core Web Vitals](https://www.jkconcepts.at/en/web-technology-glossary/#core-web-vitals) [Structured Data](https://www.jkconcepts.at/en/web-technology-glossary/#structured-data) [Schema.org](https://www.jkconcepts.at/en/web-technology-glossary/#schema-org) ## Terms starting with A Data & discoverability · Technical [#api](https://www.jkconcepts.at/en/web-technology-glossary/#api) ### What is an API? API · Application Programming Interface A defined interface through which software systems exchange data or call functions. ### Technology, example and context #### Example A website sends text to an AI model and receives the answer back via its API. #### Why does it matter? APIs enable controlled integration into existing systems; costs, limits, availability and data transfer must be planned for. #### Related terms [Tool & Function Calling](https://www.jkconcepts.at/en/ai-glossary/#tool-calling) [MCP](https://www.jkconcepts.at/en/ai-glossary/#mcp) [Cloud AI](https://www.jkconcepts.at/en/ai-glossary/#cloud-ai) CMS & platforms · Advanced [#astro](https://www.jkconcepts.at/en/web-technology-glossary/#astro) ### What is Astro? Astro · Web framework for content-focused websites Astro is a web framework that ships little browser JavaScript by default and is particularly suited to content-focused websites. ### Technology, example and context #### Technical explanation Astro renders components to HTML on the server or at build time and only activates framework components through explicit client directives. #### Example A company website is generated entirely statically and only adds small local scripts for filters and navigation. #### Related terms [SSG](https://www.jkconcepts.at/en/web-technology-glossary/#ssg) [Islands Architecture](https://www.jkconcepts.at/en/web-technology-glossary/#islands-architecture) [JavaScript](https://www.jkconcepts.at/en/web-technology-glossary/#javascript) [HTML](https://www.jkconcepts.at/en/web-technology-glossary/#html) ## Terms starting with B Basics · Basic [#backend](https://www.jkconcepts.at/en/web-technology-glossary/#backend) ### What is the backend? Backend · The server-side part of an application The backend handles business logic, data access, permissions and interfaces outside the visible browser interface. ### Technology, example and context #### Technical explanation Backend processes validate requests, coordinate services and databases and generate HTML or structured API responses. #### Example A contact backend checks inputs, limits abuse and stores an enquiry. #### Related terms [Frontend](https://www.jkconcepts.at/en/web-technology-glossary/#frontend) [Full Stack](https://www.jkconcepts.at/en/web-technology-glossary/#full-stack) [API](https://www.jkconcepts.at/en/web-technology-glossary/#api) [Database](https://www.jkconcepts.at/en/web-technology-glossary/#database) Performance & SEO · Advanced [#compression](https://www.jkconcepts.at/en/web-technology-glossary/#compression) ### What is Brotli compression? Brotli & gzip · HTTP compression HTTP compression shrinks text files during transfer and thereby reduces load time and data volume. ### Technology, example and context #### Technical explanation Client and server negotiate a method via Accept-Encoding and Content-Encoding; image formats that are already compressed usually don’t benefit. #### Example HTML, CSS, JavaScript and JSON can often be made considerably smaller. #### Related terms [HTTP Header](https://www.jkconcepts.at/en/web-technology-glossary/#http-header) [Core Web Vitals](https://www.jkconcepts.at/en/web-technology-glossary/#core-web-vitals) [Web Server](https://www.jkconcepts.at/en/web-technology-glossary/#webserver) ## Terms starting with C Performance & SEO · Basic [#cache](https://www.jkconcepts.at/en/web-technology-glossary/#cache) ### What does caching mean? Cache · Temporary storage A cache stores content that has already been computed or loaded so that it is available again more quickly. ### Technology, example and context #### Technical explanation Caching can happen in the browser, CDN, web server, application process, object cache or database system and needs clear invalidation rules. #### Example A CDN stores an image file close to the visitor and avoids repeated fetches from the origin server. #### Related terms [Cache-Control](https://www.jkconcepts.at/en/web-technology-glossary/#cache-control) [ETag](https://www.jkconcepts.at/en/web-technology-glossary/#etag) [CDN](https://www.jkconcepts.at/en/web-technology-glossary/#cdn) [Core Web Vitals](https://www.jkconcepts.at/en/web-technology-glossary/#core-web-vitals) HTTP & network · Advanced [#cache-control](https://www.jkconcepts.at/en/web-technology-glossary/#cache-control) ### What is Cache-Control? Cache-Control · HTTP caching directive Cache-Control defines whether and for how long clients or intermediate servers may store an HTTP response. ### Technology, example and context #### Technical explanation Directives such as max-age, no-cache, no-store, public, private and must-revalidate control reuse and revalidation. #### Example Fingerprinted CSS files can be stored for a long time, while HTML should usually be revalidated regularly. #### Related terms [Cache](https://www.jkconcepts.at/en/web-technology-glossary/#cache) [ETag](https://www.jkconcepts.at/en/web-technology-glossary/#etag) [HTTP Header](https://www.jkconcepts.at/en/web-technology-glossary/#http-header) [CDN](https://www.jkconcepts.at/en/web-technology-glossary/#cdn) Performance & SEO · Advanced [#canonical-url](https://www.jkconcepts.at/en/web-technology-glossary/#canonical-url) ### What is a canonical URL? Canonical URL · Preferred address of a piece of content A canonical URL marks the preferred address of content when several URLs show similar or identical content. ### Technology, example and context #### Technical explanation The link element is a strong consolidation signal, but not a redirect and not a guarantee; internal links and the sitemap should match it. #### Example Tracking parameters show the same content, while canonical points to the clean URL. #### Related terms [URL](https://www.jkconcepts.at/en/web-technology-glossary/#url) [Redirect](https://www.jkconcepts.at/en/web-technology-glossary/#redirect) [301 Redirect](https://www.jkconcepts.at/en/web-technology-glossary/#301-redirect) [XML Sitemap](https://www.jkconcepts.at/en/web-technology-glossary/#sitemap) Performance & SEO · Basic [#cdn](https://www.jkconcepts.at/en/web-technology-glossary/#cdn) ### What is a CDN? CDN · Content Delivery Network A CDN distributes and stores content across several locations so that it can be delivered closer to visitors. ### Technology, example and context #### Technical explanation Edge servers answer cacheable requests, often terminate TLS and can add protective functions such as DDoS defence or a WAF. #### Example Images and scripts of an Austrian website are loaded from regional edge locations for international visitors. #### Related terms [Cache](https://www.jkconcepts.at/en/web-technology-glossary/#cache) [Web Hosting](https://www.jkconcepts.at/en/web-technology-glossary/#webhosting) [DDoS](https://www.jkconcepts.at/en/website-security-glossary/#ddos) [Web Application Firewall](https://www.jkconcepts.at/en/website-security-glossary/#waf) CMS & platforms · Basic [#cms](https://www.jkconcepts.at/en/web-technology-glossary/#cms) ### What is a CMS? CMS · Content management system A CMS lets you maintain website content through an admin interface. ### Technology, example and context #### Technical explanation A CMS models content, user permissions, media and publishing workflows and renders or delivers web output from them. #### Example Editors change service pages without editing HTML files directly. #### Why does it matter? A CMS makes sense when content is maintained regularly by several people; it does, however, increase maintenance and security effort. #### Related terms [WordPress](https://www.jkconcepts.at/en/web-technology-glossary/#wordpress) [Headless CMS](https://www.jkconcepts.at/en/web-technology-glossary/#headless-cms) [Website](https://www.jkconcepts.at/en/web-technology-glossary/#website) [SSG](https://www.jkconcepts.at/en/web-technology-glossary/#ssg) **A CMS or custom content management?** [See custom CMS development →](https://www.jkconcepts.at/en/custom-cms/) Security · Technical [#csp](https://www.jkconcepts.at/en/web-technology-glossary/#csp) ### What is a content security policy? Content Security Policy · CSP A CSP limits the sources from which a page may load scripts, styles, images and other resources. ### Technology, example and context #### Technical explanation The HTTP policy works with directives and source expressions; nonces or hashes can mark specifically permitted inline code. #### Example script-src 'self' basically only allows scripts from the page’s own origin. #### Why does it matter? A carefully introduced CSP makes XSS harder, but can block legitimate features if misconfigured. #### Related terms [Security Headers](https://www.jkconcepts.at/en/web-technology-glossary/#security-headers) [Cross-Site Scripting](https://www.jkconcepts.at/en/website-security-glossary/#xss) [Subresource Integrity](https://www.jkconcepts.at/en/web-technology-glossary/#subresource-integrity) [HTTP Header](https://www.jkconcepts.at/en/web-technology-glossary/#http-header) **Securing your website technically?** [See website security →](https://www.jkconcepts.at/en/wordpress-security/) HTTP & network · Basic [#cookie](https://www.jkconcepts.at/en/web-technology-glossary/#cookie) ### What are cookies? Cookie · HTTP value stored by the browser A cookie is a small value that a website can set in the browser and have sent along with matching later requests. ### Technology, example and context #### Technical explanation Attributes such as Domain, Path, Expires, Secure, HttpOnly and SameSite limit lifetime and transmission. #### Example A random session identifier connects several requests to a logged-in session. #### Why does it matter? Cookies can be technically necessary or require consent and transparent privacy information. #### Related terms [Session](https://www.jkconcepts.at/en/web-technology-glossary/#session) [SameSite Cookie](https://www.jkconcepts.at/en/web-technology-glossary/#samesite-cookie) [HttpOnly](https://www.jkconcepts.at/en/web-technology-glossary/#httponly) [Secure Cookie](https://www.jkconcepts.at/en/web-technology-glossary/#secure-cookie) Performance & SEO · Advanced [#core-web-vitals](https://www.jkconcepts.at/en/web-technology-glossary/#core-web-vitals) ### What are Core Web Vitals? Core Web Vitals · Google’s user experience metrics Core Web Vitals assess key aspects of a page’s real-world loading, interactivity and layout stability. ### Technology, example and context #### Technical explanation The metrics are taken from field data or lab measurements; causes often lie in resource prioritisation, JavaScript work or unstable layouts. #### Example An image without fixed dimensions can shift content after loading and worsen CLS. #### Related terms [Lazy Loading](https://www.jkconcepts.at/en/web-technology-glossary/#lazy-loading) [Cache](https://www.jkconcepts.at/en/web-technology-glossary/#cache) [CDN](https://www.jkconcepts.at/en/web-technology-glossary/#cdn) [Responsive Web Design](https://www.jkconcepts.at/en/web-technology-glossary/#responsive-design) **Reviewing technology, performance and discoverability?** [See the website audit →](https://www.jkconcepts.at/en/website-audit/) Security · Technical [#cors](https://www.jkconcepts.at/en/web-technology-glossary/#cors) ### What is CORS? CORS · Cross-Origin Resource Sharing CORS controls which other origins browsers may allow to access a server’s resources. ### Technology, example and context #### Technical explanation Servers set Access-Control-Allow-* headers; non-simple requests can trigger an OPTIONS preflight. CORS is not server-side authentication. #### Example An API only allows browser access from the frontend’s production domain. #### Related terms [HTTP Header](https://www.jkconcepts.at/en/web-technology-glossary/#http-header) [API](https://www.jkconcepts.at/en/web-technology-glossary/#api) [CSRF](https://www.jkconcepts.at/en/website-security-glossary/#csrf) [Authentication](https://www.jkconcepts.at/en/website-security-glossary/#authentication) Data & discoverability · Advanced [#ai-crawler](https://www.jkconcepts.at/en/web-technology-glossary/#ai-crawler) ### What does Crawler & AI Crawler mean? Crawler & AI Crawler · Automated retrieval of web pages Software that retrieves web pages automatically; AI crawlers do so for AI search, training or other AI services. ### Technology, example and context #### Example A bot retrieves publicly accessible pages and processes headings, texts and links. #### Why does it matter? Technical accessibility, robots rules and clear page structures influence which content a system can process at all. #### Related terms [AI Search & Generative Search](https://www.jkconcepts.at/en/ai-glossary/#ai-search) [GEO](https://www.jkconcepts.at/en/ai-glossary/#geo) [Structured Data](https://www.jkconcepts.at/en/web-technology-glossary/#structured-data) CMS & platforms · Advanced [#csr](https://www.jkconcepts.at/en/web-technology-glossary/#csr) ### What does client-side rendering mean? CSR · Client-Side Rendering Client-side rendering generates essential parts of an interface with JavaScript in the browser. ### Technology, example and context #### Technical explanation The client loads code and data, manages the UI state and updates the display without full document navigation. #### Example A complex internal dashboard loads data via an API after startup and renders tables in the browser. #### Related terms [SPA](https://www.jkconcepts.at/en/web-technology-glossary/#spa) [SSR](https://www.jkconcepts.at/en/web-technology-glossary/#ssr) [Hydration](https://www.jkconcepts.at/en/web-technology-glossary/#hydration) [React](https://www.jkconcepts.at/en/web-technology-glossary/#react) Frontend · Basic [#css](https://www.jkconcepts.at/en/web-technology-glossary/#css) ### What is CSS? CSS · Cascading Style Sheets CSS determines the presentation, layout and responsive adaptation of HTML content. ### Technology, example and context #### Technical explanation Selectors address elements; the cascade, specificity and inheritance determine which declarations are applied as computed styles. #### Example A media query changes the layout for smaller screens. #### Related terms [HTML](https://www.jkconcepts.at/en/web-technology-glossary/#html) [Flexbox](https://www.jkconcepts.at/en/web-technology-glossary/#flexbox) [CSS Grid](https://www.jkconcepts.at/en/web-technology-glossary/#css-grid) [Media Query](https://www.jkconcepts.at/en/web-technology-glossary/#media-query) Frontend · Advanced [#css-grid](https://www.jkconcepts.at/en/web-technology-glossary/#css-grid) ### What is CSS Grid? CSS Grid · CSS Grid Layout CSS Grid is a two-dimensional layout model for rows and columns. ### Technology, example and context #### Technical explanation Explicit and implicit tracks, grid lines, areas and minmax and fr units enable flexible grids without table markup. #### Example A glossary page shows filters and results in two columns and stacks them on mobile devices. #### Related terms [CSS](https://www.jkconcepts.at/en/web-technology-glossary/#css) [Flexbox](https://www.jkconcepts.at/en/web-technology-glossary/#flexbox) [Media Query](https://www.jkconcepts.at/en/web-technology-glossary/#media-query) [Responsive Web Design](https://www.jkconcepts.at/en/web-technology-glossary/#responsive-design) ## Terms starting with D Backend & APIs · Basic [#database](https://www.jkconcepts.at/en/web-technology-glossary/#database) ### What is a database? Database · Structured data store A database stores data in a structured way and provides functions for reading, changing and securing it. ### Technology, example and context #### Technical explanation Relational systems organise data in tables and relationships; other models use documents, key-value pairs, graphs or vectors. #### Example A shop stores customers, products, orders and status changes in a database. #### Related terms [MySQL](https://www.jkconcepts.at/en/web-technology-glossary/#mysql) [Backend](https://www.jkconcepts.at/en/web-technology-glossary/#backend) [Vector Database](https://www.jkconcepts.at/en/ai-glossary/#vector-database) HTTP & network · Basic [#dns](https://www.jkconcepts.at/en/web-technology-glossary/#dns) ### What is DNS? DNS · Domain Name System DNS translates domain names into technical targets so that browsers, email servers and other services find the right systems. ### Technology, example and context #### Technical explanation Resolvers query the hierarchical DNS infrastructure for records such as A, AAAA, CNAME, MX or TXT and cache answers according to their TTL. #### Example An A record connects example.at with the IPv4 address of the web server. #### Why does it matter? Faulty DNS records can make the website and email unreachable at the same time. #### Related terms [Domain](https://www.jkconcepts.at/en/web-technology-glossary/#domain) [Web Hosting](https://www.jkconcepts.at/en/web-technology-glossary/#webhosting) [Cache](https://www.jkconcepts.at/en/web-technology-glossary/#cache) **Problems with your domain, DNS or hosting?** [See hosting help →](https://www.jkconcepts.at/en/domain-email-hosting-help/) Frontend · Advanced [#dom](https://www.jkconcepts.at/en/web-technology-glossary/#dom) ### What is the DOM? DOM · Document Object Model The DOM is the programmable tree representation of a loaded HTML or XML document. ### Technology, example and context #### Technical explanation Browsers create nodes for elements, text and other parts of the document; JavaScript can read properties and change the tree in a targeted way. #### Example A filter sets the hidden attribute on glossary cards that don’t match. #### Related terms [HTML](https://www.jkconcepts.at/en/web-technology-glossary/#html) [JavaScript](https://www.jkconcepts.at/en/web-technology-glossary/#javascript) [Frontend](https://www.jkconcepts.at/en/web-technology-glossary/#frontend) Basics · Basic [#domain](https://www.jkconcepts.at/en/web-technology-glossary/#domain) ### What is a domain? Domain · Readable name of an internet address A domain is a readable name such as jkconcepts.at under which a website or another internet service can be reached. ### Technology, example and context #### Technical explanation The Domain Name System resolves the name via DNS records into technical targets such as IP addresses or other host names. #### Example The domain example.at can point to a web server and, via separate DNS records, to an email provider. #### Why does it matter? Domain, DNS and hosting are separate building blocks and can be managed with different providers. #### Related terms [DNS](https://www.jkconcepts.at/en/web-technology-glossary/#dns) [URL](https://www.jkconcepts.at/en/web-technology-glossary/#url) [Web Hosting](https://www.jkconcepts.at/en/web-technology-glossary/#webhosting) **Problems with your domain, DNS or hosting?** [See hosting help →](https://www.jkconcepts.at/en/domain-email-hosting-help/) ## Terms starting with E HTTP & network · Technical [#etag](https://www.jkconcepts.at/en/web-technology-glossary/#etag) ### What is an ETag? ETag · Entity Tag An ETag is an identifier for a specific version of an HTTP resource. ### Technology, example and context #### Technical explanation The client later sends the value as If-None-Match; if the resource is unchanged, the server can respond with 304 without a full body. #### Example A browser validates a cached CSS file without downloading it again in full. #### Related terms [Cache](https://www.jkconcepts.at/en/web-technology-glossary/#cache) [Cache-Control](https://www.jkconcepts.at/en/web-technology-glossary/#cache-control) [HTTP Header](https://www.jkconcepts.at/en/web-technology-glossary/#http-header) Frontend · Technical [#event-loop](https://www.jkconcepts.at/en/web-technology-glossary/#event-loop) ### What is the JavaScript event loop? Event Loop · Event loop of a JavaScript runtime The event loop coordinates when JavaScript tasks and asynchronous callbacks are executed. ### Technology, example and context #### Technical explanation Once the current call stack has finished, the runtime processes queues; microtasks such as promise reactions are handled before the next regular task. #### Example A completed network request queues its callback for later processing without interrupting the current code. #### Related terms [JavaScript](https://www.jkconcepts.at/en/web-technology-glossary/#javascript) [Node.js](https://www.jkconcepts.at/en/web-technology-glossary/#nodejs) [WebSocket](https://www.jkconcepts.at/en/web-technology-glossary/#websocket) ## Terms starting with F Frontend · Advanced [#flexbox](https://www.jkconcepts.at/en/web-technology-glossary/#flexbox) ### What is Flexbox? Flexbox · CSS Flexible Box Layout Flexbox is a CSS layout model for arranging elements along a main and a cross axis. ### Technology, example and context #### Technical explanation Flex containers distribute available space via properties such as flex-grow, flex-shrink, flex-basis, justify-content and align-items. #### Example Navigation items are distributed in a row and may wrap when space is tight. #### Related terms [CSS](https://www.jkconcepts.at/en/web-technology-glossary/#css) [CSS Grid](https://www.jkconcepts.at/en/web-technology-glossary/#css-grid) [Responsive Web Design](https://www.jkconcepts.at/en/web-technology-glossary/#responsive-design) Basics · Basic [#frontend](https://www.jkconcepts.at/en/web-technology-glossary/#frontend) ### What is the frontend? Frontend · The user-facing part of an application The frontend is the part of a website or application that people see and operate. ### Technology, example and context #### Technical explanation On the web it covers HTML, CSS, JavaScript, browser APIs, state logic and communication with server-side interfaces. #### Example Forms, navigation, glossary filters and visual design are all part of the frontend. #### Related terms [Backend](https://www.jkconcepts.at/en/web-technology-glossary/#backend) [Full Stack](https://www.jkconcepts.at/en/web-technology-glossary/#full-stack) [HTML](https://www.jkconcepts.at/en/web-technology-glossary/#html) [JavaScript](https://www.jkconcepts.at/en/web-technology-glossary/#javascript) Basics · Basic [#full-stack](https://www.jkconcepts.at/en/web-technology-glossary/#full-stack) ### What does full stack mean? Full Stack · Development across frontend and backend Full stack refers to work across several layers of a web application, in particular frontend, backend and data storage. ### Technology, example and context #### Technical explanation The term describes breadth, not automatically depth; infrastructure, security, operation and architecture can be part of it too. #### Example A feature covers the form interface, API endpoint, validation and database storage. #### Related terms [Frontend](https://www.jkconcepts.at/en/web-technology-glossary/#frontend) [Backend](https://www.jkconcepts.at/en/web-technology-glossary/#backend) [Database](https://www.jkconcepts.at/en/web-technology-glossary/#database) [API](https://www.jkconcepts.at/en/web-technology-glossary/#api) ## Terms starting with H CMS & platforms · Advanced [#headless-cms](https://www.jkconcepts.at/en/web-technology-glossary/#headless-cms) ### What is a headless CMS? Headless CMS · CMS without a tightly coupled website output A headless CMS manages content and delivers it via APIs without dictating the final website interface. ### Technology, example and context #### Technical explanation Frontend and editing are decoupled; content can serve several channels, but needs a separate rendering, preview and deployment concept. #### Example Product data is delivered to the website, an app and an internal display from the same content source. #### Related terms [CMS](https://www.jkconcepts.at/en/web-technology-glossary/#cms) [API](https://www.jkconcepts.at/en/web-technology-glossary/#api) [SSG](https://www.jkconcepts.at/en/web-technology-glossary/#ssg) [Frontend](https://www.jkconcepts.at/en/web-technology-glossary/#frontend) **A CMS or custom content management?** [See custom CMS development →](https://www.jkconcepts.at/en/custom-cms/) Security · Advanced [#hsts](https://www.jkconcepts.at/en/web-technology-glossary/#hsts) ### What is HSTS? HSTS · HTTP Strict Transport Security HSTS instructs browsers to access a domain only via HTTPS for a defined period. ### Technology, example and context #### Technical explanation The Strict-Transport-Security header can include subdomains; preloading also reduces the risk on the very first visit. #### Example A browser locally replaces a later http request with https. #### Related terms [HTTPS](https://www.jkconcepts.at/en/web-technology-glossary/#https) [TLS](https://www.jkconcepts.at/en/web-technology-glossary/#tls) [Security Headers](https://www.jkconcepts.at/en/web-technology-glossary/#security-headers) [TLS Certificate](https://www.jkconcepts.at/en/web-technology-glossary/#certificate) Frontend · Basic [#html](https://www.jkconcepts.at/en/web-technology-glossary/#html) ### What is HTML? HTML · HyperText Markup Language HTML describes the content and semantic structure of a web document. ### Technology, example and context #### Technical explanation After parsing, elements and attributes form the DOM; semantic elements support browsers, search engines and assistive technologies. #### Example Headings, navigation, paragraphs, forms and images are marked up with suitable HTML elements. #### Related terms [DOM](https://www.jkconcepts.at/en/web-technology-glossary/#dom) [CSS](https://www.jkconcepts.at/en/web-technology-glossary/#css) [JavaScript](https://www.jkconcepts.at/en/web-technology-glossary/#javascript) [Web Accessibility](https://www.jkconcepts.at/en/web-technology-glossary/#accessibility) HTTP & network · Basic [#http](https://www.jkconcepts.at/en/web-technology-glossary/#http) ### What is HTTP? HTTP · Hypertext Transfer Protocol HTTP is the protocol with which clients and servers exchange requests and responses for web resources. ### Technology, example and context #### Technical explanation A message consists of a method or status, headers and optionally a body. HTTP is stateless; session state is established separately. #### Example A browser sends GET /contact/ and the server responds with status 200 and HTML. #### Related terms [HTTPS](https://www.jkconcepts.at/en/web-technology-glossary/#https) [Request & Response](https://www.jkconcepts.at/en/web-technology-glossary/#request-response) [HTTP Header](https://www.jkconcepts.at/en/web-technology-glossary/#http-header) [Cookie](https://www.jkconcepts.at/en/web-technology-glossary/#cookie) Performance & SEO · Basic [#http-404](https://www.jkconcepts.at/en/web-technology-glossary/#http-404) ### What is a 404 error? HTTP 404 · Not Found The status code 404 means that the server found no matching resource for the requested URL. ### Technology, example and context #### Technical explanation A genuine error page must still send HTTP status 404 alongside helpful content; an error page that only looks like one but returns status 200 is a soft 404. #### Example A deleted path without a suitable replacement returns a branded 404 page. #### Related terms [Redirect](https://www.jkconcepts.at/en/web-technology-glossary/#redirect) [301 Redirect](https://www.jkconcepts.at/en/web-technology-glossary/#301-redirect) [URL](https://www.jkconcepts.at/en/web-technology-glossary/#url) [XML Sitemap](https://www.jkconcepts.at/en/web-technology-glossary/#sitemap) **Is your website showing errors or down?** [See WordPress help →](https://www.jkconcepts.at/en/wordpress-help/) Performance & SEO · Basic [#http-500](https://www.jkconcepts.at/en/web-technology-glossary/#http-500) ### What does HTTP 500 mean? HTTP 500 · Internal Server Error The status code 500 reports an unexpected server-side error while processing a request. ### Technology, example and context #### Technical explanation The public response is deliberately generic; specific causes are found in application and server logs and can range from code errors to resource problems. #### Example A faulty plugin triggers an unhandled PHP exception. #### Related terms [Logging](https://www.jkconcepts.at/en/web-technology-glossary/#logging) [Monitoring](https://www.jkconcepts.at/en/web-technology-glossary/#monitoring) [Backend](https://www.jkconcepts.at/en/web-technology-glossary/#backend) [Web Server](https://www.jkconcepts.at/en/web-technology-glossary/#webserver) **Is your website showing errors or down?** [See WordPress help →](https://www.jkconcepts.at/en/wordpress-help/) HTTP & network · Advanced [#http-header](https://www.jkconcepts.at/en/web-technology-glossary/#http-header) ### What are HTTP headers? HTTP Header · Metadata of an HTTP message HTTP headers carry additional information about a request or response. ### Technology, example and context #### Technical explanation Headers control, among other things, content type, caching, authentication, compression, cookies, CORS and browser security rules. #### Example Content-Type: application/json marks a JSON response. #### Related terms [HTTP](https://www.jkconcepts.at/en/web-technology-glossary/#http) [Cache-Control](https://www.jkconcepts.at/en/web-technology-glossary/#cache-control) [Security Headers](https://www.jkconcepts.at/en/web-technology-glossary/#security-headers) [CORS](https://www.jkconcepts.at/en/web-technology-glossary/#cors) Security · Advanced [#httponly](https://www.jkconcepts.at/en/web-technology-glossary/#httponly) ### What does HttpOnly mean for cookies? HttpOnly · Cookie protection against JavaScript access HttpOnly prevents JavaScript in the browser from reading a cookie’s value directly. ### Technology, example and context #### Technical explanation The browser still sends the cookie automatically with matching HTTP requests; CSRF protection and XSS prevention therefore remain necessary. #### Example The session ID is not visible to document.cookie. #### Related terms [Cookie](https://www.jkconcepts.at/en/web-technology-glossary/#cookie) [Session Hijacking](https://www.jkconcepts.at/en/website-security-glossary/#session-hijacking) [Cross-Site Scripting](https://www.jkconcepts.at/en/website-security-glossary/#xss) [Secure Cookie](https://www.jkconcepts.at/en/web-technology-glossary/#secure-cookie) HTTP & network · Basic [#https](https://www.jkconcepts.at/en/web-technology-glossary/#https) ### What is HTTPS? HTTPS · HTTP over TLS HTTPS uses TLS to protect the connection between client and server against simple eavesdropping and tampering. ### Technology, example and context #### Technical explanation After the TLS handshake, HTTP messages are transmitted encrypted and authenticated; the certificate binds the public key to a host name. #### Example A login form does not transmit credentials as unencrypted plain text over the network. #### Why does it matter? HTTPS is a basic requirement for secure forms, modern browser features and trustworthy website operation. #### Related terms [TLS](https://www.jkconcepts.at/en/web-technology-glossary/#tls) [HTTP](https://www.jkconcepts.at/en/web-technology-glossary/#http) [HSTS](https://www.jkconcepts.at/en/web-technology-glossary/#hsts) [TLS Certificate](https://www.jkconcepts.at/en/web-technology-glossary/#certificate) **Securing your website technically?** [See website security →](https://www.jkconcepts.at/en/wordpress-security/) Frontend · Technical [#hydration](https://www.jkconcepts.at/en/web-technology-glossary/#hydration) ### What does hydration mean for websites? Hydration · Activating server-rendered HTML Hydration connects HTML that has already been rendered in the browser with JavaScript state and interactions. ### Technology, example and context #### Technical explanation The client framework reconstructs the component tree and binds events; differences between server and client output can cause hydration errors. #### Example A menu that is visible from the server becomes interactive once the JavaScript has loaded. #### Related terms [SSR](https://www.jkconcepts.at/en/web-technology-glossary/#ssr) [CSR](https://www.jkconcepts.at/en/web-technology-glossary/#csr) [Islands Architecture](https://www.jkconcepts.at/en/web-technology-glossary/#islands-architecture) [JavaScript](https://www.jkconcepts.at/en/web-technology-glossary/#javascript) ## Terms starting with I Frontend · Technical [#islands-architecture](https://www.jkconcepts.at/en/web-technology-glossary/#islands-architecture) ### What is islands architecture? Islands Architecture · Island architecture for interactive components With islands architecture, most of a page stays static while only selected components get JavaScript. ### Technology, example and context #### Technical explanation Interactive islands are hydrated or loaded independently, so the entire page doesn’t have to run as a client application. #### Example A static content page activates only search, navigation and a form as interactive parts. #### Related terms [Astro](https://www.jkconcepts.at/en/web-technology-glossary/#astro) [Hydration](https://www.jkconcepts.at/en/web-technology-glossary/#hydration) [SSG](https://www.jkconcepts.at/en/web-technology-glossary/#ssg) [JavaScript](https://www.jkconcepts.at/en/web-technology-glossary/#javascript) ## Terms starting with J Frontend · Basic [#javascript](https://www.jkconcepts.at/en/web-technology-glossary/#javascript) ### What is JavaScript? JavaScript · The programming language of the web JavaScript is a programming language for interactive browser features and many server-side applications. ### Technology, example and context #### Technical explanation Browsers run ECMAScript in a runtime with web APIs, an event loop and DOM access; modules structure larger applications. #### Example A glossary search shows matching terms as you type. #### Related terms [TypeScript](https://www.jkconcepts.at/en/web-technology-glossary/#typescript) [DOM](https://www.jkconcepts.at/en/web-technology-glossary/#dom) [Event Loop](https://www.jkconcepts.at/en/web-technology-glossary/#event-loop) [Node.js](https://www.jkconcepts.at/en/web-technology-glossary/#nodejs) Backend & APIs · Basic [#json](https://www.jkconcepts.at/en/web-technology-glossary/#json) ### What is JSON? JSON · JavaScript Object Notation JSON is a text-based data format for structured values such as objects, lists, strings, numbers and booleans. ### Technology, example and context #### Technical explanation JSON has a clearly defined syntax, but no comments, functions or dates as a type of their own. #### Example An API responds with {"status":"ok","count":3}. #### Related terms [API](https://www.jkconcepts.at/en/web-technology-glossary/#api) [REST API](https://www.jkconcepts.at/en/web-technology-glossary/#rest-api) [Structured Output](https://www.jkconcepts.at/en/ai-glossary/#structured-output) ## Terms starting with L Performance & SEO · Advanced [#lazy-loading](https://www.jkconcepts.at/en/web-technology-glossary/#lazy-loading) ### What is lazy loading? Lazy Loading · Deferred loading Lazy loading only loads content or code when it is likely to be needed. ### Technology, example and context #### Technical explanation Browsers can lazy-load images and iframes natively; bundlers split JavaScript into separately fetchable chunks via dynamic imports. #### Example Images far below the visible area are not transferred on the first page view. #### Related terms [Core Web Vitals](https://www.jkconcepts.at/en/web-technology-glossary/#core-web-vitals) [JavaScript](https://www.jkconcepts.at/en/web-technology-glossary/#javascript) [Cache](https://www.jkconcepts.at/en/web-technology-glossary/#cache) Security · Basic [#logging](https://www.jkconcepts.at/en/web-technology-glossary/#logging) ### What does logging mean? Logging · Recording events Logging records technical and security-relevant events for diagnosis, traceability and detection. ### Technology, example and context #### Technical explanation Good logs contain the time, event type and necessary context, avoid sensitive content and are protected against unnoticed tampering. #### Example Failed logins are logged with the account, time and approximate origin. #### Related terms [Monitoring](https://www.jkconcepts.at/en/web-technology-glossary/#monitoring) [HTTP 500](https://www.jkconcepts.at/en/web-technology-glossary/#http-500) [File Integrity Monitoring](https://www.jkconcepts.at/en/website-security-glossary/#file-integrity-monitoring) [Website Security](https://www.jkconcepts.at/en/website-security-glossary/#website-security) ## Terms starting with M Frontend · Advanced [#media-query](https://www.jkconcepts.at/en/web-technology-glossary/#media-query) ### What is a media query? Media Query · Conditional CSS rule for output properties A media query activates CSS rules depending on properties such as the available width or user preferences. ### Technology, example and context #### Technical explanation Besides viewport features, prefers-reduced-motion, colour scheme, pointer precision and print media can be queried, among others. #### Example From 64rem upwards, a filter bar is shown as a sidebar next to the results. #### Related terms [CSS](https://www.jkconcepts.at/en/web-technology-glossary/#css) [Responsive Web Design](https://www.jkconcepts.at/en/web-technology-glossary/#responsive-design) [Mobile First](https://www.jkconcepts.at/en/web-technology-glossary/#mobile-first) [Web Accessibility](https://www.jkconcepts.at/en/web-technology-glossary/#accessibility) Frontend · Basic [#mobile-first](https://www.jkconcepts.at/en/web-technology-glossary/#mobile-first) ### What does mobile first mean? Mobile First · Design approach starting from the small screen Mobile first starts with a clear, complete mobile presentation and extends it for larger screens. ### Technology, example and context #### Technical explanation Base rules apply to small viewports; min-width media queries add layout and features progressively. #### Example The glossary cards start as a single column and become two columns on wide screens. #### Related terms [Responsive Web Design](https://www.jkconcepts.at/en/web-technology-glossary/#responsive-design) [Media Query](https://www.jkconcepts.at/en/web-technology-glossary/#media-query) [Web Accessibility](https://www.jkconcepts.at/en/web-technology-glossary/#accessibility) Security · Basic [#monitoring](https://www.jkconcepts.at/en/web-technology-glossary/#monitoring) ### What is website monitoring? Monitoring · Ongoing system monitoring Monitoring observes the availability, performance, errors and selected security signals of a system. ### Technology, example and context #### Technical explanation Metrics, synthetic checks and log signals need thresholds, alerting paths and responsible responses so that data turns into action. #### Example An alert is triggered when the website cannot be reached or errors rise sharply. #### Related terms [Logging](https://www.jkconcepts.at/en/web-technology-glossary/#logging) [Backup](https://www.jkconcepts.at/en/website-security-glossary/#backup) [File Integrity Monitoring](https://www.jkconcepts.at/en/website-security-glossary/#file-integrity-monitoring) [Disaster Recovery](https://www.jkconcepts.at/en/website-security-glossary/#disaster-recovery) **Ongoing care for updates, backups and monitoring?** [See WordPress maintenance →](https://www.jkconcepts.at/en/wordpress-maintenance/) Backend & APIs · Advanced [#mysql](https://www.jkconcepts.at/en/web-technology-glossary/#mysql) ### What is MySQL? MySQL · Relational database system MySQL is a relational database system that stores data in tables and queries it with SQL. ### Technology, example and context #### Technical explanation Schemas, keys, indexes, transactions and constraints structure and protect data; MariaDB is a related but independent system. #### Example WordPress typically stores posts, options, users and metadata in MySQL or MariaDB. #### Related terms [Database](https://www.jkconcepts.at/en/web-technology-glossary/#database) [WordPress](https://www.jkconcepts.at/en/web-technology-glossary/#wordpress) [Backend](https://www.jkconcepts.at/en/web-technology-glossary/#backend) ## Terms starting with N Backend & APIs · Advanced [#nodejs](https://www.jkconcepts.at/en/web-technology-glossary/#nodejs) ### What is Node.js? Node.js · JavaScript runtime outside the browser Node.js runs JavaScript outside the browser and is used for servers, tools and build processes. ### Technology, example and context #### Technical explanation The runtime combines the V8 engine with event-driven I/O interfaces and a package ecosystem built around npm. #### Example Astro uses Node.js to generate the static website. #### Related terms [JavaScript](https://www.jkconcepts.at/en/web-technology-glossary/#javascript) [Backend](https://www.jkconcepts.at/en/web-technology-glossary/#backend) [Event Loop](https://www.jkconcepts.at/en/web-technology-glossary/#event-loop) [SSG](https://www.jkconcepts.at/en/web-technology-glossary/#ssg) ## Terms starting with P Backend & APIs · Basic [#php](https://www.jkconcepts.at/en/web-technology-glossary/#php) ### What is PHP? PHP · Server-side programming language PHP is a server-side programming language used particularly often for websites, APIs and content management systems. ### Technology, example and context #### Technical explanation A PHP process handles a request, runs application code and generates an HTTP response; Composer manages typical package dependencies. #### Example WordPress and WooCommerce run most of their core logic in PHP. #### Related terms [Backend](https://www.jkconcepts.at/en/web-technology-glossary/#backend) [WordPress](https://www.jkconcepts.at/en/web-technology-glossary/#wordpress) [Web Server](https://www.jkconcepts.at/en/web-technology-glossary/#webserver) [API](https://www.jkconcepts.at/en/web-technology-glossary/#api) ## Terms starting with R Performance & SEO · Advanced [#301-redirect](https://www.jkconcepts.at/en/web-technology-glossary/#301-redirect) ### What does 301 redirect mean? 301 Redirect · Permanent HTTP redirect A 301 redirect marks a permanent redirect to a new URL. ### Technology, example and context #### Technical explanation Clients and search engines may adopt the target in the long term; for unsafe methods, 308 can express preservation of the method more clearly. #### Example An old WordPress address is redirected after the relaunch to the new route with the corresponding content. #### Related terms [Redirect](https://www.jkconcepts.at/en/web-technology-glossary/#redirect) [Canonical URL](https://www.jkconcepts.at/en/web-technology-glossary/#canonical-url) [HTTP 404](https://www.jkconcepts.at/en/web-technology-glossary/#http-404) [XML Sitemap](https://www.jkconcepts.at/en/web-technology-glossary/#sitemap) **Carrying URLs and content over cleanly in a redesign?** [See website redesign →](https://www.jkconcepts.at/en/website-redesign/) Security · Advanced [#rate-limiting](https://www.jkconcepts.at/en/web-technology-glossary/#rate-limiting) ### What is rate limiting? Rate Limiting · Limiting requests Rate limiting restricts how many actions are allowed within a period of time. ### Technology, example and context #### Technical explanation Limits can apply per account, token, IP, route or risk signal; distributed systems need a shared or consistent counter. #### Example After several failed logins, further attempts are delayed step by step. #### Related terms [Brute Force](https://www.jkconcepts.at/en/website-security-glossary/#brute-force) [Bot Protection](https://www.jkconcepts.at/en/website-security-glossary/#bot-protection) [API](https://www.jkconcepts.at/en/web-technology-glossary/#api) [DDoS](https://www.jkconcepts.at/en/website-security-glossary/#ddos) Frontend · Advanced [#react](https://www.jkconcepts.at/en/web-technology-glossary/#react) ### What is React? React · JavaScript library for user interfaces React is a component-based JavaScript library for building state-driven user interfaces. ### Technology, example and context #### Technical explanation Components produce declarative element trees; React coordinates state changes, rendering and, depending on the runtime, server- or client-side execution. #### Example A complex dashboard breaks navigation, filters, tables and charts down into reusable components. #### Related terms [JavaScript](https://www.jkconcepts.at/en/web-technology-glossary/#javascript) [CSR](https://www.jkconcepts.at/en/web-technology-glossary/#csr) [SSR](https://www.jkconcepts.at/en/web-technology-glossary/#ssr) [Hydration](https://www.jkconcepts.at/en/web-technology-glossary/#hydration) Performance & SEO · Basic [#redirect](https://www.jkconcepts.at/en/web-technology-glossary/#redirect) ### What is a redirect? Redirect · HTTP redirect A redirect tells the client that a resource is available at a different URL. ### Technology, example and context #### Technical explanation 3xx status codes distinguish, among other things, permanent and temporary targets and how the original HTTP method is handled. #### Example After a relaunch, the old service URL leads permanently to the matching new page. #### Related terms [301 Redirect](https://www.jkconcepts.at/en/web-technology-glossary/#301-redirect) [URL](https://www.jkconcepts.at/en/web-technology-glossary/#url) [Canonical URL](https://www.jkconcepts.at/en/web-technology-glossary/#canonical-url) [HTTP 404](https://www.jkconcepts.at/en/web-technology-glossary/#http-404) HTTP & network · Basic [#request-response](https://www.jkconcepts.at/en/web-technology-glossary/#request-response) ### What are request and response? Request & Response · Request and response A client sends a request; the server processes it and returns a response. ### Technology, example and context #### Technical explanation Requests contain a method, target, headers and optional data. Responses contain a status code, headers and an optional response body. #### Example POST /api/contact submits form data and receives a success or error message. #### Related terms [HTTP](https://www.jkconcepts.at/en/web-technology-glossary/#http) [API](https://www.jkconcepts.at/en/web-technology-glossary/#api) [HTTP Header](https://www.jkconcepts.at/en/web-technology-glossary/#http-header) [Backend](https://www.jkconcepts.at/en/web-technology-glossary/#backend) Frontend · Basic [#responsive-design](https://www.jkconcepts.at/en/web-technology-glossary/#responsive-design) ### What is responsive web design? Responsive Web Design · Adaptive web layout Responsive web design adapts content, layout and interaction to different screen sizes and input methods. ### Technology, example and context #### Technical explanation Flexible grids, intrinsic sizing, responsive media and media and container queries avoid separate device-specific layouts. #### Example On small screens, filter chips can be scrolled horizontally instead of taking up many rows. #### Related terms [Mobile First](https://www.jkconcepts.at/en/web-technology-glossary/#mobile-first) [Media Query](https://www.jkconcepts.at/en/web-technology-glossary/#media-query) [Web Accessibility](https://www.jkconcepts.at/en/web-technology-glossary/#accessibility) [CSS Grid](https://www.jkconcepts.at/en/web-technology-glossary/#css-grid) Backend & APIs · Advanced [#rest-api](https://www.jkconcepts.at/en/web-technology-glossary/#rest-api) ### What is a REST API? REST API · HTTP interface following REST principles A REST API provides resources and actions via clearly defined HTTP endpoints. ### Technology, example and context #### Technical explanation Typical interfaces use HTTP methods, status codes, URLs and representation-based data formats; REST itself does not require JSON. #### Example GET /api/orders/42 reads an order, PATCH updates selected fields. #### Related terms [API](https://www.jkconcepts.at/en/web-technology-glossary/#api) [HTTP](https://www.jkconcepts.at/en/web-technology-glossary/#http) [JSON](https://www.jkconcepts.at/en/web-technology-glossary/#json) [Authentication](https://www.jkconcepts.at/en/website-security-glossary/#authentication) Performance & SEO · Basic [#robots-txt](https://www.jkconcepts.at/en/web-technology-glossary/#robots-txt) ### What is robots.txt? robots.txt · Crawler control file robots.txt gives cooperating crawlers rules for fetching certain areas of a website. ### Technology, example and context #### Technical explanation The file lives at the origin under /robots.txt; Disallow does not prevent access and is no reliable protection against indexing or attackers. #### Example Internal search results are excluded from crawling by search engine bots. #### Related terms [XML Sitemap](https://www.jkconcepts.at/en/web-technology-glossary/#sitemap) [Crawler & AI Crawler](https://www.jkconcepts.at/en/web-technology-glossary/#ai-crawler) [Canonical URL](https://www.jkconcepts.at/en/web-technology-glossary/#canonical-url) ## Terms starting with S Security · Technical [#samesite-cookie](https://www.jkconcepts.at/en/web-technology-glossary/#samesite-cookie) ### What does SameSite mean for cookies? SameSite Cookie · Limiting cross-site cookie transmission SameSite controls when a browser sends cookies with requests from a different site context. ### Technology, example and context #### Technical explanation Strict, Lax and None have different rules for navigation and embedding; SameSite=None requires Secure. #### Example A Lax session cookie reduces many simple CSRF scenarios without preventing normal link navigation. #### Related terms [Cookie](https://www.jkconcepts.at/en/web-technology-glossary/#cookie) [CSRF](https://www.jkconcepts.at/en/website-security-glossary/#csrf) [Secure Cookie](https://www.jkconcepts.at/en/web-technology-glossary/#secure-cookie) [HttpOnly](https://www.jkconcepts.at/en/web-technology-glossary/#httponly) Data & discoverability · Advanced [#schema-org](https://www.jkconcepts.at/en/web-technology-glossary/#schema-org) ### What does Schema.org mean? Schema.org · Vocabulary for structured web data A shared vocabulary that websites use to describe people, organisations, offers, terms and other content. ### Technology, example and context #### Example A glossary uses DefinedTermSet and DefinedTerm to mark up terms and definitions in a machine-readable way. #### Why does it matter? Schema.org creates a common language for systems; markup alone does not replace helpful visible content, however. #### Related terms [Structured Data](https://www.jkconcepts.at/en/web-technology-glossary/#structured-data) [Entity](https://www.jkconcepts.at/en/ai-glossary/#entity) [GEO](https://www.jkconcepts.at/en/ai-glossary/#geo) Security · Advanced [#secure-cookie](https://www.jkconcepts.at/en/web-technology-glossary/#secure-cookie) ### What does Secure mean for cookies? Secure Cookie · Cookie sent only over HTTPS The Secure attribute ensures that a cookie is only sent over encrypted HTTPS connections. ### Technology, example and context #### Technical explanation It doesn’t protect against client-side reading and should be combined for sensitive cookies with HttpOnly, SameSite and narrow domain and path limits. #### Example A session cookie is never transmitted over an unencrypted HTTP connection. #### Related terms [Cookie](https://www.jkconcepts.at/en/web-technology-glossary/#cookie) [HTTPS](https://www.jkconcepts.at/en/web-technology-glossary/#https) [HttpOnly](https://www.jkconcepts.at/en/web-technology-glossary/#httponly) [SameSite Cookie](https://www.jkconcepts.at/en/web-technology-glossary/#samesite-cookie) Security · Advanced [#security-headers](https://www.jkconcepts.at/en/web-technology-glossary/#security-headers) ### What are security headers? Security Headers · HTTP security headers Security headers give the browser additional security rules for a website. ### Technology, example and context #### Technical explanation CSP, HSTS, frame-ancestors, Referrer-Policy and other headers limit loading sources, protocol downgrades, embedding and the sharing of information. #### Example A CSP prevents arbitrary third-party scripts from being executed on a page. #### Related terms [Content Security Policy](https://www.jkconcepts.at/en/web-technology-glossary/#csp) [HSTS](https://www.jkconcepts.at/en/web-technology-glossary/#hsts) [HTTP Header](https://www.jkconcepts.at/en/web-technology-glossary/#http-header) [Cross-Site Scripting](https://www.jkconcepts.at/en/website-security-glossary/#xss) **Securing your website technically?** [See website security →](https://www.jkconcepts.at/en/wordpress-security/) Backend & APIs · Advanced [#session](https://www.jkconcepts.at/en/web-technology-glossary/#session) ### What is a session? Session · Server-side session state A session keeps related user requests in a shared state across several page views. ### Technology, example and context #### Technical explanation Usually the server stores the state and the browser only sends a random session ID in a protected cookie. #### Example After login, the server recognises the logged-in user from the session ID. #### Related terms [Cookie](https://www.jkconcepts.at/en/web-technology-glossary/#cookie) [Authentication](https://www.jkconcepts.at/en/website-security-glossary/#authentication) [Session Hijacking](https://www.jkconcepts.at/en/website-security-glossary/#session-hijacking) [Backend](https://www.jkconcepts.at/en/web-technology-glossary/#backend) CMS & platforms · Advanced [#spa](https://www.jkconcepts.at/en/web-technology-glossary/#spa) ### What is a single page application? SPA · Single Page Application An SPA loads one application document and then updates views mainly in the browser. ### Technology, example and context #### Technical explanation Client-side routing and state management replace many full page navigations; data usually comes via APIs. #### Example A project management tool switches between tasks and views without reloading the whole document. #### Related terms [CSR](https://www.jkconcepts.at/en/web-technology-glossary/#csr) [Web App](https://www.jkconcepts.at/en/web-technology-glossary/#web-app) [API](https://www.jkconcepts.at/en/web-technology-glossary/#api) [React](https://www.jkconcepts.at/en/web-technology-glossary/#react) CMS & platforms · Advanced [#ssg](https://www.jkconcepts.at/en/web-technology-glossary/#ssg) ### What is a static site generator? SSG · Static Site Generation With static site generation, finished HTML pages are created before publication instead of on every request. ### Technology, example and context #### Technical explanation A build reads templates and data, produces files and can deliver them via simple web space or a CDN. #### Example Astro generates all known pages as static HTML files during the build. #### Related terms [Astro](https://www.jkconcepts.at/en/web-technology-glossary/#astro) [SSR](https://www.jkconcepts.at/en/web-technology-glossary/#ssr) [CSR](https://www.jkconcepts.at/en/web-technology-glossary/#csr) [CDN](https://www.jkconcepts.at/en/web-technology-glossary/#cdn) CMS & platforms · Advanced [#ssr](https://www.jkconcepts.at/en/web-technology-glossary/#ssr) ### What does SSR mean? SSR · Server-Side Rendering Server-side rendering generates HTML on the server, typically for each request or via a server-side cache. ### Technology, example and context #### Technical explanation The server runs application logic and serialises the view; client-side hydration can then add interactivity. #### Example A personalised portal renders a user-specific overview page after login. #### Related terms [SSG](https://www.jkconcepts.at/en/web-technology-glossary/#ssg) [CSR](https://www.jkconcepts.at/en/web-technology-glossary/#csr) [Hydration](https://www.jkconcepts.at/en/web-technology-glossary/#hydration) [Backend](https://www.jkconcepts.at/en/web-technology-glossary/#backend) Data & discoverability · Advanced [#structured-data](https://www.jkconcepts.at/en/web-technology-glossary/#structured-data) ### What is structured data? Structured Data · Machine-readable page data Machine-readable information that describes the content and meaning of a page in defined fields. ### Technology, example and context #### Example A website additionally marks up its organisation, services or defined terms as JSON-LD. #### Why does it matter? Structured data makes unambiguous interpretation easier, but must match the visible content and be technically correct. #### Related terms [Schema.org](https://www.jkconcepts.at/en/web-technology-glossary/#schema-org) [Entity](https://www.jkconcepts.at/en/ai-glossary/#entity) [Knowledge Graph](https://www.jkconcepts.at/en/ai-glossary/#knowledge-graph) Security · Technical [#subresource-integrity](https://www.jkconcepts.at/en/web-technology-glossary/#subresource-integrity) ### What is subresource integrity? Subresource Integrity · SRI SRI lets browsers check whether an externally loaded resource matches the expected cryptographic hash exactly. ### Technology, example and context #### Technical explanation The integrity attribute contains one or more hash values; for cross-origin resources, the CORS configuration must allow the check. #### Example A CDN script is only executed if its content matches the stored SHA-384 hash. #### Related terms [Content Security Policy](https://www.jkconcepts.at/en/web-technology-glossary/#csp) [Software Supply Chain Attack](https://www.jkconcepts.at/en/website-security-glossary/#supply-chain-attack) [CORS](https://www.jkconcepts.at/en/web-technology-glossary/#cors) [Hashing](https://www.jkconcepts.at/en/website-security-glossary/#hashing) ## Terms starting with T HTTP & network · Advanced [#tls](https://www.jkconcepts.at/en/web-technology-glossary/#tls) ### What is TLS? TLS · Transport Layer Security TLS is a protocol for encrypted network connections that are protected against tampering. ### Technology, example and context #### Technical explanation The handshake negotiates the version and cryptographic methods, checks certificates and derives session keys for symmetric encryption. #### Example HTTPS, secure mail transfer and many APIs use TLS to protect the transport. #### Related terms [HTTPS](https://www.jkconcepts.at/en/web-technology-glossary/#https) [TLS Certificate](https://www.jkconcepts.at/en/web-technology-glossary/#certificate) [Encryption](https://www.jkconcepts.at/en/website-security-glossary/#encryption) [HSTS](https://www.jkconcepts.at/en/web-technology-glossary/#hsts) HTTP & network · Advanced [#certificate](https://www.jkconcepts.at/en/web-technology-glossary/#certificate) ### What is an SSL certificate? TLS Certificate · Digital certificate for a host name A TLS certificate confirms that a public key belongs to a domain name. ### Technology, example and context #### Technical explanation Browsers check the signature, validity, host name and the certificate chain up to a trusted certificate authority. #### Example Let’s Encrypt provides automatable domain certificates for HTTPS. #### Related terms [TLS](https://www.jkconcepts.at/en/web-technology-glossary/#tls) [HTTPS](https://www.jkconcepts.at/en/web-technology-glossary/#https) [Encryption](https://www.jkconcepts.at/en/website-security-glossary/#encryption) Frontend · Advanced [#typescript](https://www.jkconcepts.at/en/web-technology-glossary/#typescript) ### What is TypeScript? TypeScript · JavaScript with static type checking TypeScript extends JavaScript with static types and additional development tools. ### Technology, example and context #### Technical explanation The compiler checks type relationships before execution and produces JavaScript; the type information itself is normally not available at runtime. #### Example An interface describes which fields a glossary term must have. #### Related terms [JavaScript](https://www.jkconcepts.at/en/web-technology-glossary/#javascript) [Frontend](https://www.jkconcepts.at/en/web-technology-glossary/#frontend) [Node.js](https://www.jkconcepts.at/en/web-technology-glossary/#nodejs) ## Terms starting with U Basics · Basic [#url](https://www.jkconcepts.at/en/web-technology-glossary/#url) ### What is a URL? URL · Uniform Resource Locator A URL describes the address of a specific resource on the web. ### Technology, example and context #### Technical explanation It can contain scheme, host, port, path, query string and fragment, for example https://example.at/search/?q=test#results. #### Example The domain names the host; the path /contact/ denotes a resource on that host. #### Related terms [Domain](https://www.jkconcepts.at/en/web-technology-glossary/#domain) [HTTP](https://www.jkconcepts.at/en/web-technology-glossary/#http) [Canonical URL](https://www.jkconcepts.at/en/web-technology-glossary/#canonical-url) [Redirect](https://www.jkconcepts.at/en/web-technology-glossary/#redirect) ## Terms starting with W Frontend · Basic [#accessibility](https://www.jkconcepts.at/en/web-technology-glossary/#accessibility) ### What is web accessibility? Web Accessibility · Accessible websites for everyone Web accessibility ensures that people with different abilities and assistive tools can use digital content. ### Technology, example and context #### Technical explanation Semantic HTML, keyboard operation, focus management, contrast, clear labels and robust interfaces to assistive technologies are central foundations. #### Example A search field has a visible label, and filter buttons expose their pressed state programmatically. #### Related terms [HTML](https://www.jkconcepts.at/en/web-technology-glossary/#html) [Responsive Web Design](https://www.jkconcepts.at/en/web-technology-glossary/#responsive-design) [Core Web Vitals](https://www.jkconcepts.at/en/web-technology-glossary/#core-web-vitals) **Reviewing technology, performance and discoverability?** [See the website audit →](https://www.jkconcepts.at/en/website-audit/) Basics · Basic [#web-app](https://www.jkconcepts.at/en/web-technology-glossary/#web-app) ### What is a web app? Web App · Web application A web app is an application operated in the browser in which users edit data or carry out specific workflows. ### Technology, example and context #### Technical explanation Web apps combine a user interface in the browser with server-side logic, APIs, databases and often a user login. #### Example An internal order portal replaces shared Excel files and coordination by email. #### Why does it matter? The distinction from a website affects architecture, security needs, development costs and ongoing support. #### Related terms [Website](https://www.jkconcepts.at/en/web-technology-glossary/#website) [Frontend](https://www.jkconcepts.at/en/web-technology-glossary/#frontend) [Backend](https://www.jkconcepts.at/en/web-technology-glossary/#backend) [API](https://www.jkconcepts.at/en/web-technology-glossary/#api) **Turning an internal workflow into a web app?** [See custom software →](https://www.jkconcepts.at/en/custom-software/) Basics · Basic [#webhosting](https://www.jkconcepts.at/en/web-technology-glossary/#webhosting) ### What is web hosting? Web Hosting · Operating environment for websites Web hosting provides storage, computing power and network access so that a website can be delivered on the internet. ### Technology, example and context #### Technical explanation Depending on the plan, web server, runtime, database, TLS, backups and email run on shared, virtual, dedicated or managed infrastructure. #### Example WordPress hosting runs PHP, connects to MySQL and delivers images and stylesheets. #### Why does it matter? The performance, security, backups and support of the hosting affect how reliable the website is. #### Related terms [Domain](https://www.jkconcepts.at/en/web-technology-glossary/#domain) [Web Server](https://www.jkconcepts.at/en/web-technology-glossary/#webserver) [DNS](https://www.jkconcepts.at/en/web-technology-glossary/#dns) [CDN](https://www.jkconcepts.at/en/web-technology-glossary/#cdn) **Problems with your domain, DNS or hosting?** [See hosting help →](https://www.jkconcepts.at/en/domain-email-hosting-help/) HTTP & network · Basic [#webserver](https://www.jkconcepts.at/en/web-technology-glossary/#webserver) ### What is a web server? Web Server · Server for HTTP requests A web server accepts HTTP requests and delivers files or dynamically generated responses to browsers and other clients. ### Technology, example and context #### Technical explanation Software such as nginx or Apache handles TLS, routing, caching, compression and forwarding to application processes. #### Example The web server delivers a static HTML file directly or forwards a PHP request to PHP-FPM. #### Related terms [HTTP](https://www.jkconcepts.at/en/web-technology-glossary/#http) [Request & Response](https://www.jkconcepts.at/en/web-technology-glossary/#request-response) [Web Hosting](https://www.jkconcepts.at/en/web-technology-glossary/#webhosting) [Backend](https://www.jkconcepts.at/en/web-technology-glossary/#backend) Security · Technical [#webauthn](https://www.jkconcepts.at/en/web-technology-glossary/#webauthn) ### What is WebAuthn? WebAuthn · Web Authentication API WebAuthn is the browser API for strong public-key logins with passkeys and security keys. ### Technology, example and context #### Technical explanation The server sends a challenge; the authenticator signs it for the specific relying party, preventing simple phishing reuse. #### Example A hardware security key confirms the administrator login. #### Related terms [Passkey](https://www.jkconcepts.at/en/website-security-glossary/#passkey) [Authentication](https://www.jkconcepts.at/en/website-security-glossary/#authentication) [MFA / 2FA](https://www.jkconcepts.at/en/website-security-glossary/#mfa) [Phishing](https://www.jkconcepts.at/en/website-security-glossary/#phishing) Backend & APIs · Advanced [#webhook](https://www.jkconcepts.at/en/web-technology-glossary/#webhook) ### What is a webhook? Webhook · Event-driven HTTP call A webhook automatically informs another system about an event via HTTP. ### Technology, example and context #### Technical explanation The sender calls a registered URL; receivers should check signatures, tolerate retries and make processing idempotent. #### Example A payment provider tells the shop that a payment has been completed successfully. #### Related terms [API](https://www.jkconcepts.at/en/web-technology-glossary/#api) [REST API](https://www.jkconcepts.at/en/web-technology-glossary/#rest-api) [Authentication](https://www.jkconcepts.at/en/website-security-glossary/#authentication) [Rate Limiting](https://www.jkconcepts.at/en/web-technology-glossary/#rate-limiting) Basics · Basic [#website](https://www.jkconcepts.at/en/web-technology-glossary/#website) ### What is a website? Website · A connected web presence A website is a web presence reachable via a domain, made up of one or more related pages. ### Technology, example and context #### Technical explanation Browsers load documents and resources from a web server via HTTP or HTTPS. Navigation, URLs and links connect the individual pages into a shared offering. #### Example A company website contains, for example, a homepage, services, projects, contact and legal pages. #### Why does it matter? For structure, operation and cost, what matters is whether a simple website, a CMS, a shop or a web app is needed. #### Related terms [Domain](https://www.jkconcepts.at/en/web-technology-glossary/#domain) [Web Hosting](https://www.jkconcepts.at/en/web-technology-glossary/#webhosting) [HTML](https://www.jkconcepts.at/en/web-technology-glossary/#html) [Web App](https://www.jkconcepts.at/en/web-technology-glossary/#web-app) **Building a new website the right way?** [See website design →](https://www.jkconcepts.at/en/website-design/) HTTP & network · Technical [#websocket](https://www.jkconcepts.at/en/web-technology-glossary/#websocket) ### What is a WebSocket? WebSocket · Persistent bidirectional web connection WebSocket enables a permanently open connection over which client and server can send messages at any time. ### Technology, example and context #### Technical explanation After an HTTP upgrade, the connection uses its own frame-based protocol over TCP and needs explicit authentication and connection logic. #### Example Chats, live dashboards or collaborative editing transmit updates without constant polling. #### Related terms [HTTP](https://www.jkconcepts.at/en/web-technology-glossary/#http) [API](https://www.jkconcepts.at/en/web-technology-glossary/#api) [Authentication](https://www.jkconcepts.at/en/website-security-glossary/#authentication) CMS & platforms · Basic [#wordpress](https://www.jkconcepts.at/en/web-technology-glossary/#wordpress) ### What is WordPress? WordPress · Open-source content management system WordPress is a widely used open-source CMS for websites, editorial content and, with extensions, online shops. ### Technology, example and context #### Technical explanation WordPress is based mainly on PHP and MySQL, has theme, plugin, hook, role and REST API systems and needs ongoing updates. #### Example A custom theme reflects the corporate design, while structured content fields make maintenance easier. #### Why does it matter? Quality depends heavily on architecture, extensions, maintenance, hosting and security configuration. #### Related terms [CMS](https://www.jkconcepts.at/en/web-technology-glossary/#cms) [PHP](https://www.jkconcepts.at/en/web-technology-glossary/#php) [MySQL](https://www.jkconcepts.at/en/web-technology-glossary/#mysql) [WordPress Hardening](https://www.jkconcepts.at/en/website-security-glossary/#wordpress-hardening) **Building WordPress your way – and maintainable?** [See WordPress development →](https://www.jkconcepts.at/en/wordpress-development/) Security · Technical [#wp-cron](https://www.jkconcepts.at/en/web-technology-glossary/#wp-cron) ### What is WP-Cron? WP-Cron · Event scheduling in WordPress WP-Cron runs scheduled WordPress tasks, but by default is triggered by page views. ### Technology, example and context #### Technical explanation With irregular or high traffic, a real system cron can be more reliable; blocked or overloaded cron runs affect updates and background jobs. #### Example Scheduled publications and WooCommerce background tasks depend on cron events running reliably. #### Related terms [WordPress](https://www.jkconcepts.at/en/web-technology-glossary/#wordpress) [Monitoring](https://www.jkconcepts.at/en/web-technology-glossary/#monitoring) [Backend](https://www.jkconcepts.at/en/web-technology-glossary/#backend) ## Terms starting with X Performance & SEO · Basic [#sitemap](https://www.jkconcepts.at/en/web-technology-glossary/#sitemap) ### What is a sitemap? XML Sitemap · Machine-readable list of URLs An XML sitemap lists indexable URLs and optional update dates for search engines. ### Technology, example and context #### Technical explanation It helps with discovery, but replaces neither internal linking nor indexability and doesn’t guarantee inclusion in the search index. #### Example A static build generates a sitemap from all indexable routes. #### Related terms [robots.txt](https://www.jkconcepts.at/en/web-technology-glossary/#robots-txt) [Canonical URL](https://www.jkconcepts.at/en/web-technology-glossary/#canonical-url) [HTTP 404](https://www.jkconcepts.at/en/web-technology-glossary/#http-404) [Crawler & AI Crawler](https://www.jkconcepts.at/en/web-technology-glossary/#ai-crawler) Technology that fits the project ## Website, CMS or custom web app? The right architecture depends on content, workflows, interfaces, maintenance and the actual goal.