mastra dev

The mastra dev command launches a development server that serves your Mastra application locally.

REST API Endpoints

mastra dev spins up REST API endpoints for your agents and workflows, such as:

• POST /api/agents/:agentId/generate
• POST /api/agents/:agentId/stream
• POST /api/workflows/:workflowId/start
• POST /api/workflows/:workflowId/:instanceId/event
• GET /api/workflows/:workflowId/:instanceId/status

By default, the server runs at http://localhost:4111, but you can change the port with the --port flag.

UI Playground

mastra dev creates a UI with an agent chat interface, a workflow visualizer and a tool playground.

OpenAPI Specification

mastra dev provides an OpenAPI spec at:

• GET /openapi.json

Summary

mastra dev makes it easy to develop, debug, and iterate on your AI logic in a self-contained environment before deploying to production.

• Mastra Dev reference