Inspecting agents and workflows with `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.

Using the Client SDK

The easiest way to interact with your local Mastra server is through our TypeScript/JavaScript Client SDK. Install it with:

npm install @mastra/client-js

Then configure it to point to your local server:

import { MastraClient } from "@mastra/client-js";
 
const client = new MastraClient({
  baseUrl: "http://localhost:4111",
});
 
// Example: Interact with a local agent
const agent = client.getAgent("my-agent");
const response = await agent.generate({
  messages: [{ role: "user", content: "Hello!" }],
});

The client SDK provides type-safe wrappers for all API endpoints, making it much easier to develop and test your Mastra applications locally.

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.

Creating Projects Integrations

Inspecting agents and workflows with mastra Dev