bun.sh/docs/runtime/web-apis.md

Some Web APIs aren't relevant in the context of a server-first runtime like Bun, such as the DOM API or History API. Many others, though, are broadly useful outside of the browser context; when possible, Bun implements these Web-standard APIs instead of introducing new APIs.

The following Web APIs are partially or completely supported.

{% table %}

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• HTTP
• fetch Response Request Headers AbortController AbortSignal

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• URLs
• URL URLSearchParams

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• Web Workers
• Worker self.postMessage structuredClone. Missing MessagePort, MessageChannel, BroadcastChannel.

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• Streams
• ReadableStream WritableStream TransformStream ByteLengthQueuingStrategy CountQueuingStrategy and associated classes

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• Blob
• Blob

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• WebSockets
• WebSocket

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• Encoding and decoding
• atob btoa TextEncoder TextDecoder

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• JSON
• JSON

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• Timeouts
• setTimeout clearTimeout

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• Intervals
• setIntervalclearInterval

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• Crypto
• crypto SubtleCrypto CryptoKey

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• Debugging

• console performance

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• Microtasks
• queueMicrotask

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• Errors
• reportError

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• User interaction
• alert confirm prompt (intended for interactive CLIs)

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• Realms
• ShadowRealm

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• Events
• EventTarget Event ErrorEvent CloseEvent MessageEvent

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{% /table %}