Mastra: the open-source JavaScript framework for building agents

Hey everyone 🙂 we’re Sam, Shane and Abhi.

What we’re building: Mastra (https://mastra.ai) is an open-source JavaScript SDK for building agents on top of Vercel’s AI SDK.

https://www.youtube.com/watch?v=8o_Ejbcw5s8

Our backstory: Previously, we built Gatsby, the open-source React web framework.

We noticed our friends building AI applications getting stuck debugging prompts, figuring out why their agents called (or didn’t call) tools, and writing lots of custom memory retrieval logic.

In October, we started building Mastra, and last week we went viral on Hacker News and Github and went from 1,500 to 7,500 stars.

Mastra use-cases: Fireworks AI is using us to build agentic workflows. YC companies are using Mastra to automate support, build CAD diagrams, scrape the web for contact info, automate medical transcriptions, generate financial documents, and create code generation products.

Mastra allows you to create workflow graphs that can suspend/resume, build RAG pipelines, write evals, give agents memory, create multi-agent workflows, and test it all in a local playground.

Here’s a weather agent and the agent playground (with tracing built in!):

You can deploy Mastra agents and workflows to a serverless platform like Vercel, Cloudflare, Netlify, any cloud service that can run Node.js, or our own hosting platform with evals and tracing.

How to get started: Just head over to the command line and install:npm create mastra

Happy building 🙂

PS: we’ve spent a lot of time this batch doing AI engineering whiteboarding sessions with other batch startups, walking through architecture and best practices, so we decided to write a book to help people get up to speed faster: Principles of Building AI Agents.

Follow @mastra_ai on Twitter/X and tweet at us and we’ll get you a physical copy!