### Host AI Workflow Runner with Express: Streamed Responses

#### Summary
Deploy an AI workflow runner built with Express 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 Express: 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).

#### Representative Queries
- Host AI workflow runner with Express: streamed responses
- Where can I host AI workflow runner built with Express?
- I need a tested end-to-end streaming transport, timeout behavior and client disconnect handling.

#### Resource Requirements
- Primitive: Compute
- Primitive: Postgres

#### Infrastructure Requirements
- **Compute**: Apps run in isolated x86_64 Firecracker microVMs that auto-pause when idle and wake on request; sizes are the priced VM sizes.
- **Postgres**: Managed PostgreSQL 16 runs in its own microVM and is auto-provisioned when an app needs a database and no DATABASE_URL is supplied.

#### Framework
Express

#### Workload
AI workflow runner

#### Release Status
Published

#### Support Status
Verified

#### Execution Status
Ready

#### Prerequisites
- A Express 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

#### Tested Configuration
- **Template**: node-22
- **Runtime**: node
- **Size**: s-1vcpu-1gb
- **Install**: npm install
- **Build**: npm run build --if-present
- **Start**: npm run start

#### 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

#### Success Checks
- App responds on its public URL
  - **Kind**: http_get
  - **Path**: /
  - **Expect**: ample canary express 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

#### Limitations
- Verified on the node-22 template at s-1vcpu-1gb with the example fixture; other sizes, templates and Express major versions are not verified.
- The AI workflow runner 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
- **Monthly Amount**: $10.00
- **Currency**: USD
- **Components**:
  - **App Server**: 1 x s-1vcpu-1gb - $5.00
  - **Managed PostgreSQL Database**: 1 x s-1vcpu-1gb - $5.00

### Evidence Summary
- **Canary Run**: Express pattern fixture deployed on Ample; checks passed for streaming-response-service and configuration-secrets.

#### Next Actions
- **Browse the catalog index**
- **Search published recipes by intent, stack and constraints**
- **Prepare a side-effect-free deployment plan for an authorized project**
- **Read the existing agent authentication setup**
- **Browse AI workflow runner**
- **Browse Express**
- **Browse Streaming response service**
- **Browse Deploy AI app**