### Host mobile backend with Express: Postgres-backed state

Deploy a mobile backend built with Express on Ample using the durable job state 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 jobs table with a state and attempts counter, processing inside a row-locked transaction, and a second run that is a no-op (job=done attempts=1 idempotent=true). Not separately tested: your job types, payload schema and retry policy; treat the mobile backend-specific behavior as your application code.

#### Representative Queries
- Host mobile backend with Express: Postgres-backed state
- Where can I host Mobile backend built with Express?
- I need a durable state schema and retry/recovery semantics implemented by application code.

### 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

### Resource Requirements
- primitive:compute
- primitive:postgres

### Infrastructure Requirements
1. **Compute**: Apps run in isolated x86_64 Firecracker microVMs that auto-pause when idle and wake on request; sizes are the priced VM sizes.
2. **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.

### 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**: 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).
   Command: `ample deploy . --name  --public`
4. **Verify**: Fetch the live URL and the pattern self-test route(s) (/p/durable-job-state) 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 Express major versions are not verified.
- The mobile backend itself (your job types, payload schema and retry policy) 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.

### Cost Estimate
- **Currency**: USD
- **Monthly Amount**: 10.0
- **Components**:
  - App server: size s-1vcpu-1gb, quantity 1.0, monthly amount 5.0
  - Managed PostgreSQL database: size s-1vcpu-1gb, quantity 1.0, monthly amount 5.0

### Success Checks
1. **App responds on its public URL**: Verify by checking `/` expects to receive `ample canary express patterns`.
2. **Durable-job-state self-test**: Verify by checking `/p/durable-job-state` expects to receive `job=done attempts=1 idempotent=true`.

### Next Actions
1. **Browse the catalog index**: [GET /v1/catalog](https://api.ample.computer/v1/catalog)
2. **Search published recipes by intent, stack and constraints**: [POST /v1/catalog/search](https://api.ample.computer/v1/catalog/search)
3. **Prepare a side-effect-free deployment plan for an authorized project**: [POST /v1/catalog/plan](https://api.ample.computer/v1/catalog/plan)
4. **Read the existing agent authentication setup**: [GET /mcp/setup](https://api.ample.computer/mcp/setup)