What it is
Vercel's AI SDK is an open-source TypeScript library for building AI apps and agents. It puts providers like OpenAI, Anthropic and Google behind one API, with streaming, tool calling and structured outputs, plus UI hooks for React, Next.js, Vue and Svelte. It runs in any Node.js environment, not just on Vercel.
How to use it
- Generate text or structured data with a single function and switch providers in one line.
- Stream responses to your UI with hooks like useChat.
- Give the model tools so it can handle multi-step tasks as an agent.
- Validate outputs with Zod schemas to get typed JSON.
- Route models through Vercel's AI Gateway if you'd rather use one account.
What it's good for
- A startup adding an AI chat to its Next.js app in an afternoon.
- A product team testing the same flow across several models before picking a provider.
- A developer extracting structured data from emails and PDFs with type validation.
Pros
- One unified API for dozens of model providers
- UI hooks for React, Vue and Svelte with streaming built in
- Free and open source under Apache 2.0
- Typed structured outputs with Zod schemas
Cons
- TypeScript and JavaScript only
- Low-level: memory, durable workflows and evals are up to you
- Major versions have shipped breaking changes that require migrations
