mastra-ai/mastra

Built on a unified model routing layer supporting 40+ LLM providers, Mastra offers graph-based workflows with explicit control flow (`.then()`, `.branch()`, `.parallel()`) alongside autonomous agents with tool use and reasoning. Features like human-in-the-loop suspension, conversation/semantic memory management, RAG integration, and MCP server support enable complex agentic applications, while built-in evals and observability tooling support production deployment across React, Next.js, Node.js, or standalone servers.

21,938 stars and 1,070,215 monthly downloads. Actively maintained with 707 commits in the last 30 days. Available on npm.