CopilotKit
Build AI copilots for your product — React components in minutes.
MIT-licensed framework with drop-in CopilotKit components, CoAgents for human-in-the-loop, and LangChain integration. Works with OpenAI, Anthropic, and custom LLMs.
The Vercel AI SDK is itself open source (Apache-2.0) and free to use — it's a TypeScript toolkit for calling LLM providers through a unified API. Where teams look elsewhere is usually less about the SDK's license and more about wanting a higher-level toolkit for building the actual chat/copilot UI, or wanting to avoid coupling their AI features to Vercel's broader platform (like the AI Gateway) as the stack grows.
CopilotKit sits at a different layer — it's focused on shipping in-product AI copilots with ready-made React components, rather than being a low-level model-calling SDK.
FAQ
Is there a free, open-source alternative to Vercel AI SDK?
Yes. CopilotKit is open source and free to self-host, though it targets a different layer — building in-product AI copilots rather than raw model calls.
What's the best open-source alternative to Vercel AI SDK?
CopilotKit is worth evaluating if what you actually need is pre-built React components for an in-app copilot rather than a low-level SDK for calling models.
What are the top open-source alternatives to Vercel AI SDK?
Browse all open-source alternatives to Vercel AI SDK above, or explore the full Developer Tools category for more options.