Host ai workflow runner with Express: Postgres-backed state

Summary

Deploy a ai workflow runner 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 ai workflow runner-specific behavior as your application code.

Infrastructure requirements

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

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

Exact tested configuration

• template: node-22
• runtime: node
• size: s-1vcpu-1gb
• install: npm install
• build: npm run build --if-present
• start: npm run start

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 durable job state: 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). 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).

   ample deploy . --name <app-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 <deployment_id> --kind build then --kind runtime.

   ample logs <deployment_id> --kind build
   

Tested examples

• Express pattern fixture (tests/deploy-canaries/express-patterns): Multi-pattern Express app whose durable job state module was checked live; the module is under tests/deploy-canaries/_pattern-modules.

Success checks

• app responds on its public URL (/ on the live URL, expect ample canary express patterns)
• durable-job-state self-test (/p/durable-job-state on the live URL, expect job=done attempts=1 idempotent=true)

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 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.
• 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

Estimated 10.00 USD per month.

• app server x1 s-1vcpu-1gb: 5.00 USD
• managed PostgreSQL database x1 s-1vcpu-1gb: 5.00 USD

Verification evidence

• canary_run on 2026-09-21T02:34:39Z at revision 1d28ae0-dirty (CLI 0.1.21): Express pattern fixture deployed on Ample; checks passed for durable-job-state and configuration-secrets. Pattern proof: 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). (expires 2027-03-20T02:34:39Z)
• canary_run on 2026-09-20T01:54:51Z at revision 199ff1dfd52683832ae75d3f98b53a7a4bff7f96-dirty (CLI e3181f5): The same Express app deployed with a --release-command migration; the marker it created was readable after activation. (expires 2027-03-19T01:54:51Z)

Last verified: 2026-09-21T02:34:39Z

Execution binding

MCP tool ample_deploy, binding state current, required scopes: servers:write, databases:read.