Vercel AI SDK

The AI SDK comes from Vercel, the company behind Next.js, Turborepo, SWR and shadcn/ui. The landing page doesn't tell a founding story, so this review won't invent one. What it does show is a team that already maintains popular JavaScript tooling and needed a standard way to call LLMs from TypeScript. The result is an open-source toolkit, installed with a plain `npm install ai`, that the site says pulls 31.2M weekly downloads and has 27.4K GitHub stars and 733+ contributors. Those numbers are large. This isn't a side project that'll vanish next quarter.

The pitch is simple: one unified TypeScript API for text generation, structured objects, tool calls and agents, across 100+ models. You call `generateText` with a model string and a prompt, and switching providers is, in Vercel's words, "one line of code." Streaming works without custom parsing, fallbacks are built in, and there's a separate AI SDK UI layer with framework-agnostic hooks for chat and generative interfaces. It supports React, Next.js, Vue, Svelte, Angular, Nuxt, Solid and Node.js, so you aren't locked into Next.js even though Vercel makes it. The testimonial from Elementor's Adir Duchan is telling: his team built an agent with 40+ tools and said streaming, tool call repair and message management already had clean APIs. OpenCode also runs on it.

The Vercel origin cuts both ways. The SDK is free and framework agnostic, but the landing page steers you toward Vercel's paid platform products: AI Gateway (100+ models with "no markup" and no juggling API keys), Vercel Sandbox for running agent-generated code, and the new Workflows package for long-running agents that survive function timeouts. You don't need any of them to use the SDK. Still, it's worth knowing where the defaults point. If you're building AI features in TypeScript, this is the closest thing to a default choice right now.