# Examples

Each example lives in `examples/` and is runnable. Use them as templates. See [Getting Started](Getting-Started.md) for initial setup.

## Basic (`examples/basic`)
- What: Minimal STDIO server using `FastMCP::new(...).run()`.
- Run: `cd examples/basic && cargo run`.
- Highlight: Logging via `tracing_subscriber::fmt()`; good starting point for CLI integrations.

## SSE (`examples/sse`)
- What: Server-Sent Events transport on `http://127.0.0.1:3000`.
- Run: `cd examples/sse && cargo run --features sse`.
- Highlight: Uses `SseTransport::new()` + `run_sse_server`; shows endpoints `/mcp/sse` (events) and `/mcp/message` (POST). First event returns `connectionId`; include it in POSTs.

## WebSocket (`examples/websocket`)
- What: Bidirectional WebSocket transport on `ws://127.0.0.1:3001`.
- Run: `cd examples/websocket && cargo run --features websocket`.
- Highlight: `WebSocketTransport::new()` + `run_websocket_server`; server-initiated messages go to current connection unless `metadata.connectionId` is provided.

## Middleware (`examples/middleware`)
- What: Logging + rate limit + bearer auth middleware chain.
- Run: `cd examples/middleware && RUST_LOG=info cargo run`.
- Highlight: Demonstrates middleware ordering and error handling; tools `greet` and `calculate` show validation with `MCPError::InvalidParams`.

## Subscriptions (`examples/subscriptions`)
- What: Subscribable resources (`time://current`, `counter://value`, `file:///config.json`) plus tools to mutate state.
- Run: `cd examples/subscriptions && cargo run`.
- Highlight: Shows subscription lifecycle (`resources/subscribe`, notifications, `resources/unsubscribe`); includes background ticker to simulate updates.

## Complete (`examples/complete`)
- What: All features in one place (tools, resources, prompts, state, lifecycle hooks).
- Run: `cd examples/complete && cargo run`.
- Highlights:
  - Tools: math (add/multiply/factorial/is_prime), strings (reverse/uppercase/count_words), complex types (`greet_person`, `calculate_stats` with validation).
  - Resources: `system://info`, `server://status` (uses shared state).
  - Prompts: code review, docs, bug analysis.
  - State: `State` holds `AppConfig`; lifecycle hooks initialize/clean up.

## CLI Templates (`fastrmcp-cli`)
- `fastrmcp new <name> --template basic|sse|websocket|middleware|subscriptions|complete` mirrors the above examples.
- See `fastrmcp-cli/README.md` in the repo.

Related: [Transports Guide](Transports-Guide.md) for client snippets • [Middleware Cookbook](Middleware-Cookbook.md) for extending the middleware example.

[Back to Home](Home.md)