# Host mcp server with Fastify: streamed responses

Deploy a mcp server built with Fastify on Ample using the streaming response service pattern. Compute runs the app in an isolated microVM behind a public HTTPS URL, a managed PostgreSQL 16 database is auto-provisioned and injected as DATABASE_URL. Verified on Fastify: a Server-Sent Events endpoint read incrementally through the public HTTPS gateway: five one-second chunks arrived spread over time with the first within seconds (not buffered), a 70-second stream of 36 chunks completed past common 60-second idle timeouts, and a client that disconnected after two chunks was observed and recorded by the server (disconnected=true). Not separately tested: your event schema, reconnection strategy and any per-request duration ceiling beyond the 70 seconds measured; treat the mcp server-specific behavior as your application code.

### Representative Queries
- Host mcp server with Fastify: streamed responses
- Where can I host MCP server built with Fastify?
- I need a tested end-to-end streaming transport, timeout behavior and client disconnect handling.

### Prerequisites
- A Fastify project that builds and starts with the documented commands (npm install, npm run build --if-present, npm run start on the node-22 template)
- A PostgreSQL driver reading DATABASE_URL at runtime (auto-provisioned when omitted, or supplied with --env)
- An Ample account token with servers:write, databases:read

### Workflow Steps
1. **Build and start**  
   npm install, npm run build --if-present, npm run start on the node-22 template. The server must bind 0.0.0.0 on PORT.

2. **Implement the pattern on PostgreSQL**  
   The fixture's module implements streaming response service: a Server-Sent Events endpoint read incrementally through the public HTTPS gateway: five one-second chunks arrived spread over time with the first within seconds (not buffered), a 70-second stream of 36 chunks completed past common 60-second idle timeouts, and a client that disconnected after two chunks was observed and recorded by the server (disconnected=true). Copy the approach into your schema; keep migrations idempotent and run them with --release-command.

3. **Deploy**  
   Run the synchronous deploy once and read the result (exit 0 live, 1 failed, 2 blocked). Re-running with no change is a no-op.  
   Command: `ample deploy . --name  --public`

4. **Verify**  
   Fetch the live URL and the pattern self-test route(s) (/p/streaming-response-service) from the example; then run your own checks. On failure read `ample logs  --kind build` then `--kind runtime`.  
   Command: `ample logs  --kind build`

### Limitations
- Verified on the node-22 template at s-1vcpu-1gb with the example fixture; other sizes, templates and Fastify major versions are not verified.
- The mcp server itself (your event schema, reconnection strategy and any per-request duration ceiling beyond the 70 seconds measured) is application code and was not separately tested; the pattern checks are what was verified.
- Region, compliance attestations and request-duration limits are unknown and not claimed.
- Apps auto-pause when idle and wake on the next request; always-on is an operator setting, not a plan feature.
- Managed PostgreSQL 16 only; extensions, connection limits and backup or restore procedures are not verified; apps and their databases are placed together.

### Cost Estimate
- **Currency:** USD
- **Monthly Amount:** 10.0
- **Components:**  
  - **app server:** s-1vcpu-1gb, quantity: 1.0, monthly amount: 5.0  
  - **managed PostgreSQL database:** s-1vcpu-1gb, quantity: 1.0, monthly amount: 5.0  
- **Note:** Always-on monthly price of the tested sizes; apps and databases auto-pause when idle. Buckets are allocation-priced per quota and not included.

### Examples
- **Fastify pattern fixture**  
  Multi-pattern Fastify app whose streaming response service module was checked live; the module is under tests/deploy-canaries/_pattern-modules.  
  Source ref: `tests/deploy-canaries/fastify-patterns`

### Success Checks
- **app responds on its public URL**  
  - Kind: http_get
  - Path: /
  - Expect: ample canary fastify patterns
- **streaming-response-service self-test**  
  - Kind: http_get
  - Path: /p/streaming-response-service
  - Expect: an SSE stream: data: id=, then chunk events one interval apart (read incrementally: first chunk within seconds, chunks spread over the interval), then data: done; /status?id= reports sent=N disconnected=true|false done=true|false

### Next Actions
1. **Browse the catalog index**  
   - Action ID: browse-catalog
   - Method: GET
   - Relative Path: /v1/catalog
2. **Search published recipes by intent, stack and constraints**  
   - Action ID: search-recipes
   - Method: POST
   - Relative Path: /v1/catalog/search
   - Parameters: {"body":{"limit":5,"query":"Host mcp server with Fastify: streamed responses"}}
3. **Prepare a side-effect-free deployment plan for an authorized project**  
   - Action ID: plan:page:recipes:mcp-server:fastify:response-streaming
   - Method: POST
   - Relative Path: /v1/catalog/plan
   - Parameters: {"body":{"inputs":{},"projectId":"","recipeId":"page:recipes:mcp-server:fastify:response-streaming","recipeRevision":"r1"}}