Mastra

Mastra is an open-source TypeScript framework for building production AI agents, giving you agents, tools, memory, workflows, RAG, evals, and observability in a single cohesive package. Install it with npm create mastra@latest, define an agent in under 20 lines of TypeScript, and have a working REST API in minutes — no Python environment, no multi-library stitching. Why Mastra Is the TypeScript AI Framework to Watch in 2026 Mastra is the TypeScript-first AI agent framework built by the team behind Gatsby — the same engineers who made static-site generation mainstream for JavaScript developers. With 23.2k GitHub stars, $35M in total funding (including a $22M Series A led by Spark Capital announced in April 2026), and enterprise deployments at Brex, Docker, Elastic, MongoDB, Salesforce, Replit, and SoftBank, Mastra has moved from interesting experiment to production infrastructure. The Marsh McLennan enterprise search agent built on Mastra is used by 100,000+ employees every day. Brex’s Mastra-powered agents contributed directly to their $5.1B Capital One acquisition. These aren’t toy demos — they are mission-critical workloads. For JavaScript and TypeScript developers who’ve been watching the Python AI ecosystem from the sidelines, Mastra is the on-ramp. The CEO Sam Bhagwat has cited data that 60–70% of YC X25 agent startups are building in TypeScript, signaling a clear ecosystem shift. ...

Introduction: Why Mastra Is the TypeScript AI Framework to Watch in 2026 The AI agent ecosystem has a Python problem. Not with Python itself—it works fine—but with the fact that most agents ship as web services, and the teams building those services increasingly write TypeScript. Sam Bhagwat, CEO of Mastra, noted on Hacker News that 60–70% of YC X25 agent startups are building in TypeScript, not Python. The tooling hasn’t caught up. LangChain, CrewAI, and AutoGen all originated in Python, leaving TypeScript developers either wrapping Python services or cobbling together their own agent infrastructure. ...