Best assistant-ui Alternatives

Open-source TypeScript toolkit by Vercel for building AI-powered apps with streaming chat UIs, structured outputs, tool calling, and agent workflows. Framework-agnostic core with integrations for React, Next.js, Svelte, Vue, and Nuxt. Supports a broad AI SDK v6 provider catalog including OpenAI, Anthropic, Google, xAI, Mistral, Bedrock, Groq, and OpenAI-compatible providers. Includes useChat and useCompletion hooks for rapid UI development. The standard SDK for adding AI features to web apps.

TypeScript-native framework for building AI agents and workflows with great developer experience. Provides primitives for agents with tool calling, RAG pipelines, workflow orchestration with branching/parallel steps, and integration connectors. First-class TypeScript support with type-safe tool definitions. Local dev server with playground UI for testing. Growing as a LangChain alternative for TypeScript developers building AI apps.