Host rest api with Express: Postgres-backed state

Summary

Deploy an Express REST API whose durable state lives in a managed PostgreSQL 16 database. With no DATABASE_URL supplied, Ample provisions the database and injects the connection string as an encrypted environment variable; the API stores rows with pg and serves them from a public HTTPS URL.

Representative Queries

• Host rest api with Express: Postgres-backed state
• Where can I host REST API built with Express?
• I need a durable state schema and retry/recovery semantics implemented by application code.

Resource Requirements

• primitive:compute
• primitive:postgres

Infrastructure Requirements

• Compute:

  • Summary: Apps run in isolated x86_64 Firecracker microVMs that auto-pause when idle and wake on request; sizes are the priced VM sizes.
  • Status: verified
  • More Info

• Postgres:

  • Summary: Managed PostgreSQL 16 runs in its own microVM and is auto-provisioned when an app needs a database and no DATABASE_URL is supplied.
  • Status: verified
  • More Info

Prerequisites

• A package.json with a start script that listens on process.env.PORT (default 3000) and 0.0.0.0
• The pg driver (or another PostgreSQL client) reading process.env.DATABASE_URL
• Tables created by the app or by a --release-command migration, not assumed to exist
• An Ample account token with servers:write and databases:read

Workflow Steps

1. Check the start script
   Ample runs npm install, npm run build --if-present and npm run start on the node-22 template. The server must bind 0.0.0.0 and read PORT.

2. Read DATABASE_URL at runtime
   Create a pg Pool from process.env.DATABASE_URL. Do not hard-code localhost credentials; a local .env is replaced by the managed database in production.

3. Deploy
   Run the existing synchronous deploy once from the project directory and read the result. Exit 0 is live, 1 is failed, 2 is blocked on a required preflight action. Re-running with no change is a content-addressed no-op.

   ample deploy . --name  --public --format json
   

4. Verify
   Fetch the live URL and run the success checks below. On failure read the build log, then the runtime log, fix the cause and deploy again; do not blind-retry.

   ample logs  --kind build
   

Examples

• Express + pg canary
  Express API with POST /items and GET /items backed by an auto-provisioned managed PostgreSQL database. Source

Success Checks

• Root route responds

  • Kind: http_get
  • Path: /
  • Expect: ample canary express postgres api

• Database insert and count succeed

  • Kind: http_get
  • Path: /items
  • Expect: postgres=ok

Limitations

• Verified on the node-22 template at s-1vcpu-1gb; other templates and sizes are not verified by this recipe.
• 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 managed databases are placed together; cross-node shared databases are unsupported.

Cost Estimate

• Currency: USD
• Monthly Amount: $10.00
• Basis: Size prices from pricing.toml (loaded by the API) at build revision 1ac5595375130d45290090e82ed0f554ccd45405-dirty

Components

• App server

  • Size: s-1vcpu-1gb
  • Quantity: 1.0
  • Monthly Amount: $5.00

• Managed PostgreSQL database

  • Size: s-1vcpu-1gb
  • Quantity: 1.0
  • Monthly Amount: $5.00

Note: Apps and managed databases auto-pause when idle; the estimate is the always-on monthly price of the tested sizes. Plan quotas and budgets apply.