Studio

Studio provides an interactive UI for building, testing, and managing your agents, workflows, and tools. Run it locally during development, or deploy it to production so your team can manage agents, monitor performance, and gain insights through built-in observability.

Add authentication to protect your deployed Studio with login screens, role-based access control, and permission-based UI rendering so you can control what each team member can see and do. You can also create a project in Mastra Cloud for a hosted option.

Start Studio

If you created your application with create mastra, start the development server using the dev script. You can also run it directly with mastra dev.

npm

npm run dev

pnpm

pnpm run dev

Yarn

yarn dev

Bun

bun run dev

Once the server is running, you can:

• Open the Studio UI at http://localhost:4111/ to interact with your agents, workflows, and tools.
• Visit http://localhost:4111/swagger-ui to discover and interact with the underlying REST API.

To run Studio in production, see Deploy Studio.

Studio UI

The Studio UI lets you interact with your agents, workflows, and tools, observe exactly what happens under the hood with each interaction, and tweak things as you go.

Agents

Chat with your agent directly, dynamically switch models, and tweak settings like temperature and top-p to understand how they affect the output.

When you interact with your agent, you can follow each step of its reasoning, view tool call outputs, and observe traces and logs to see how responses are generated. You can also attach scorers to measure and compare response quality over time.

Workflows

Visualize your workflow as a graph and run it step by step with a custom input. During execution, the interface updates in real time to show the active step and the path taken.

When running a workflow, you can also view detailed traces showing tool calls, raw JSON outputs, and any errors that might have occurred along the way.

Tools

Run tools in isolation to observe their behavior. Test them before assigning them to your agent, or isolate them to debug issues should something go wrong.

Processors

View the input and output processors attached to each agent. The agent detail panel lists every processor by name and type, so you can verify your guardrails, token limiters, and custom processors are wired up correctly before testing.

See Processors and Guardrails for configuration details.

MCP

List the MCP servers attached to your Mastra instance and explore their available tools.

Observability

When you run an agent or workflow, the Observability tab displays traces that highlight the key AI operations such as model calls, tool executions, and workflow steps. Follow these traces to see how data moves, where time is spent, and what's happening under the hood.

Tracing filters out low-level framework details so your traces stay focused and readable.

Scorers

The Scorers tab displays the results of your agent's scorers as they run. When messages pass through your agent, the defined scorers evaluate each output asynchronously and render their results here. This allows you to understand how your scorers respond to different interactions, compare performance across test cases, and identify areas for improvement.

Datasets

Create and manage collections of test cases to evaluate your agents and workflows. Import items from CSV or JSON, define input and ground-truth schemas, and pin to specific versions so you can reproduce experiments exactly. Run experiments with scorers to compare quality across prompts, models, or code changes.

See Datasets overview for the full API and versioning details.

REST API

Studio is backed by a complete set of REST API routes that let you programmatically interact with your agents, workflows, and tools. These are the same routes exposed by the Mastra Server, so everything you build against locally works identically in production.

You can explore all available endpoints in the OpenAPI specification at http://localhost:4111/api/openapi.json, which details every endpoint and its request and response schemas.

To explore the API interactively, visit the Swagger UI at http://localhost:4111/swagger-ui. Here, you can discover endpoints and test them directly from your browser.

note

The OpenAPI and Swagger endpoints are disabled in production by default. To enable them, set server.build.openAPIDocs and server.build.swaggerUI to true respectively.

Configuration

By default, Studio runs at http://localhost:4111. You can change the host, port, and studioBase in the Mastra server configuration.

For production deployments, see Deploy Studio to learn about hosting Studio alongside your server, as a standalone SPA, or on a CDN.

Add authentication to control who can access Studio in production. Studio displays the appropriate login UI, which can be an SSO button, an email/password form, or both. All API routes require authentication. This applies to any request made to your Mastra API, whether from Studio or a direct API call.

Mastra also supports HTTPS development through the --https flag, which automatically creates and manages certificates for your project. When you run mastra dev --https, a private key and certificate are generated for localhost (or your configured host). Visit the HTTPS reference to learn more.

Next steps

• Learn more about Mastra's suggested project structure.
• Integrate Mastra with your frontend framework of choice - Next.js, React, or Astro.