A backward-compatible CSS language extension inspired by Sass that supports variables, mixins, operations, and functions.

OpenAPI

A specification language for defining HTTP APIs, typically written in YAML or JSON.

A set of criteria defined by the independent Acceptable Ads Committee that allows publishers to reach ad-blocking users with respectful, non-intrusive and relevant ads.

Text

The plain text document format.

XML

A markup language and file format for storing, transmitting, and reconstructing structured data in a platform-independent way.

Markdown

A lightweight markup language used to add formatting to plain text documents using simple, human-readable syntax.

Humans.txt

A plain text file that allows website creators to identify and credit the people involved in developing a website.

RelMeAuth

A proposed open standard for using rel-me links to profiles on OAuth supporting services to authenticate via either those profiles or your own site.

IDN

Internationalized Domain Names allow people around the world to use domain names in local languages, such as Arabic, Chinese, or Cyrillic.

WebAssembly

A portable binary instruction format that runs in modern web browsers with near-native performance, enabling frontend coding in languages that were not traditionally used for web interfaces, such as C/C++, C#, and Rust.

Prerender

A deprecated browser hint that instructed web browsers to preload and render a web page in the background before navigation occurred.

LLMs.txt

A proposed standard that provides structured content and instructions to guide large language models in understanding and summarizing a website's content.

JSON Web Token

An open standard (RFC 7519) that defines a compact and self-contained way for securely transmitting information between parties as a JSON object.

XRDS

An XML-based file format that provides a list of service endpoints (e.g., OpenID) available on a website.

A non-proprietary protocol for encrypting email using public key cryptography.

Rack

A minimal, modular interface and invocation convention that operates between Ruby web servers and web applications to standardize how HTTP requests and responses are exchanged.

OpenTelemetry

An open-source, vendor-neutral observability framework and toolkit for collecting, processing, and exporting telemetry data such as traces, metrics, and logs.

Webmention

A simple protocol to notify any URL when a website links to it, and for web pages to request notifications when somebody links to them.

ESI

A simple markup language used to define web page components for dynamic assembly and delivery of web applications at the edge of the Internet.

ActivityPub

A decentralized social networking protocol used by various Fediverse services such as Mastodon, Pixelfed, and PeerTube.

XSLT

A language designed for transforming XML documents into other documents.