Mastra

Mastra develops an open-source TypeScript framework for building AI agents and AI-powered applications. The framework bundles the primitives teams need to move from prototype to production: agents defined with instructions, models and tools; a graph-based workflow engine with sequential steps, parallel branches, conditional logic and loops; memory (message persistence, semantic recall and "observational memory"); tool definitions shareable across agents via MCP; human-in-the-loop suspension and tool approval; supervisor agents; and workspaces providing filesystem access, sandboxed code execution and reusable skill files. A unified model router connects to models from OpenAI, Anthropic, Google, xAI and other providers through one interface, with the company citing 40+ providers and more than 1,000 models. Mastra integrates with Next.js, React, Astro, Express, SvelteKit and Hono, or can be deployed as a standalone server.

The project ships production tooling alongside the framework: evals and scorers, tracing, logs, metrics on latency, cost, model calls and tool usage, versioned datasets built from traces and user feedback, and guardrails/processors intended to sanitize outputs and mitigate prompt injection. Mastra Studio is an interactive UI (locally at port 4111 or cloud-based) for running agents and workflows, swapping models, inspecting traces, editing prompts and creating datasets, including by non-engineering domain experts. In April 2026 the company announced that Mastra is also a platform, comprising cloud and self-hosted Mastra Studio, Mastra Server for deploying agents and workflows, and a Memory Gateway that can supply agent memory to projects using other frameworks as well.

The GitHub monorepo (mastra-ai/mastra) uses a dual-license model with the core framework and the majority of the repository under Apache License 2.0. The project maintains a public Discord community, documentation, templates, a course and YouTube material, and the CLI entry point is `npm create mastra@latest`.

Founding story

Founders Sam Bhagwat, Abhi Aiyer and Shane Thomas previously worked together on Gatsby, an early frontend framework for modern web apps, where Bhagwat was a co-founder, Aiyer principal engineer and Thomas staff engineer and head of product. In October 2024, while struggling to build sales agents with existing tooling, they returned from a weekend AI hackathon (described in the Series A post as an NYC AI hackathon) and decided to build better agent tooling instead. They joined Y Combinator in January 2025, saw usage take off around mid-February, and raised a seed round in March after YC.

Business model

Open-source framework distributed via npm and GitHub under a dual license (Apache 2.0 core), monetized through a commercial platform layer. Self-hosting of Mastra projects is offered at $0/month, with an enterprise tier sold on custom pricing that adds RBAC, SSO, IAM and network policy integration, deployment keeping traces, prompts and outputs inside the customer VPC, and a single flat annual fee rather than per-trace or per-seat metering.

Free self-hosted open-source tier plus a custom-priced enterprise offering billed as one flat annual fee (no per-trace or per-seat metering), covering enterprise controls and in-VPC data residency. Hosted components include Mastra Cloud/Studio and Mastra Server.

Traction

As of the 2025 seed announcement, Mastra reported roughly 190k weekly npm downloads one year after launch — a level Gatsby took four years to reach — and 'millions of downloads each month' per the about page. The GitHub repository shows 27.4k stars, 2.7k forks and 18,331 commits. Publicly cited deployments include Replit Agent 3 creating thousands of Mastra agents/sandboxes daily, Salesforce's agentic IDE running on a Mastra harness for non-Claude models (100K developers), Marsh McLennan enterprise agentic search used by 100k+ people daily, a Sanity content agent scaled to 30K+ organizations, ~50K agent runs per month inside MongoDB infrastructure, and use at SoftBank, Brex, Factorial, Indeed, Workday, PayPal, Adobe, PLAID, Elastic and Docker.

Latest developments

On 2026-04-09 Mastra announced a $22M Series A led by Spark Capital, bringing total capital raised to $35M, and simultaneously launched the Mastra platform: cloud-based and self-hosted Mastra Studio (evals, logs, traces, datasets, annotations), Mastra Server for deploying agents and workflows, and a Memory Gateway providing agent memory to Mastra and non-Mastra projects. The company said it had recently shipped parallel tool calls, subagents, sandboxes, filesystems and skills as agent primitives, along with auth and RBAC in Studio, and was working on heartbeat, channels, browser access, web data and annotations.