page:recipes:graphql api:fastify:response streaming

Host graphql api with Fastify: streamed responses

Deploy a graphql api 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 graphql api-specific behavior as your application code.

Representative Queries

• Host graphql api with Fastify: streamed responses
• Where can I host GraphQL API 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 <your-app-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

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: Expect an HTTP GET on / to return ample canary fastify patterns.
• Streaming-response-service self-test: Expect an HTTP GET on /p/streaming-response-service to return an SSE stream.

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 graphql api itself is application code and was not separately tested; the pattern checks are verified.

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.

Additional Resources

• HTML Documentation: Link
• Markdown Documentation: Link
• JSON Documentation: Link