@mastra/core/dist/docs/references/reference-file-based-agents-server.md

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# Server

Mastra configures its HTTP [server](https://mastra.ai/docs/server/mastra-server) from a `server.ts` file directly under `src/mastra/`. The server exposes agents, workflows, and other registered primitives as REST endpoints, and the file default-exports the same `ServerConfig` shape you'd pass to [`new Mastra()`](https://mastra.ai/reference/core/mastra-class).

Use this page for the file-based convention. For server features, middleware, custom routes, generated API docs, and deployment behavior, see [Server overview](https://mastra.ai/docs/server/mastra-server).

## Quickstart

Create `src/mastra/server.ts` and default-export a `ServerConfig` object:

```typescript
import type { ServerConfig } from '@mastra/core/server'

export default {
  port: 4111,
  host: '0.0.0.0',
} satisfies ServerConfig
```

## Common configurations

`server.ts` can configure the same server options as code registration:

| Need                                  | Use                                       |
| ------------------------------------- | ----------------------------------------- |
| Bind to a deployment platform address | `host` and `port`                         |
| Restrict browser access               | `cors`                                    |
| Add webhooks or health checks         | `apiRoutes`                               |
| Enable generated API docs             | `build.openAPIDocs` and `build.swaggerUI` |

See [Mastra server](https://mastra.ai/docs/server/mastra-server), [middleware](https://mastra.ai/docs/server/middleware), and [custom API routes](https://mastra.ai/docs/server/custom-api-routes) for examples.

## Precedence with code

Code-registered server config wins over `server.ts`. Routes added during startup, such as channel webhooks, are preserved when file-based server config is applied.