Runtime APIs

The Workers runtime is designed to be JavaScript standards compliant Open external link and web-interoperable. Wherever possible, it uses web platform APIs, so that code can be reused across client and server, as well as across WinterCG Open external link JavaScript runtimes.

The Workers runtime also implements a subset of Node.js APIs as an optional, opt-in compatibility layer.

• Bindings (env): Worker Bindings that allow for interaction with other Cloudflare Resources.
• Cache: Control reading and writing from the Cloudflare global network cache.
• Console: Supported methods of the console API in Cloudflare Workers
• Context (ctx): The Context API in Cloudflare Workers, including waitUntil and passThroughOnException.
• Encoding: Takes a stream of code points as input and emits a stream of bytes.
• Fetch: An interface for asynchronously fetching resources via HTTP requests inside of a Worker.
• Handlers: Methods, such as fetch(), on Workers that can receive and process external inputs.
• Headers: Access HTTP request and response headers.
• HTMLRewriter: Build comprehensive and expressive HTML parsers inside of a Worker application.
• Node.js compatibility: Implemented Node.js runtime APIs and enablement instructions for your Worker project.
• Performance and timers: Measure timing, performance, and timing of subrequests and other operations.
• Remote-procedure call (RPC): The built-in, JavaScript-native RPC system built into Workers and Durable Objects.
• Request: Interface that represents an HTTP request.
• Response: Interface that represents an HTTP response.
• Streams: A web standard API that allows JavaScript to programmatically access and process streams of data.
• TCP sockets: Use the connect() API to create outbound TCP connections from Workers.
• Web Crypto: A set of low-level functions for common cryptographic tasks.
• Web standards: Standardized APIs for use by Workers running on Cloudflare's global network.
• WebAssembly (Wasm): Execute code written in a language other than JavaScript or write an entire Cloudflare Worker in Rust.
• WebSockets: Communicate in real time with your Cloudflare Workers.