Why web-ai-sdk
web-ai-sdk is a TypeScript SDK for the Web’s Built-in AI APIs: the browser-native LanguageModel (Prompt), Writer, Rewriter, Proofreader, Translator, Summarizer, LanguageDetector, and document.modelContext (WebMCP) surfaces.
Not a provider SDK
Section titled “Not a provider SDK”It is not a provider SDK for OpenAI, Anthropic, Google AI Studio, or other server-side models. Where a tool like Vercel’s AI SDK focuses on building AI apps across model providers and frameworks (usually with a server in the loop), web-ai-sdk focuses on making the browser’s own, on-device AI APIs easier to use directly from TypeScript.
If your code calls a hosted model behind an API key, reach for a provider SDK. If your code wants to run on the model the browser ships, on-device, with no key and no server, that is what web-ai-sdk wraps.
What the SDK owns
Section titled “What the SDK owns”The Built-in AI APIs are young and shifting. Every app that touches them re-implements the same lifecycle, so web-ai-sdk owns it once:
- Feature detection and availability checks, with a no-op fallback when an API is missing
- Session creation, reuse, and cleanup
- Streaming with chunk smoothing and
AbortSignalwiring - Opt-in result caching
You build against one stable, typed surface instead of coupling your whole app to today’s experimental API shape. See Architecture for how the packages are organized and Browser support for where each one runs today.