# Configure build and start for Express

## Summary

Configure build and start for an Express app on Ample. Ample detects Node, runs npm install and npm run build --if-present, and starts the app with npm run start on the node-22 template; the app only has to bind 0.0.0.0 on PORT.

## Infrastructure requirements

- [Compute](/discover/primitive/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.)

## Prerequisites

- A package.json with a start script
- A server that listens on process.env.PORT and 0.0.0.0
- An Ample account token with servers:write

## Exact tested configuration

- template: `node-22`
- runtime: `node`
- size: `s-1vcpu-1gb`
- install: `npm install`
- build: `echo no build needed`
- start: `npm run start`

## Steps

1. **Pin what detection cannot infer.** If the start command is not in package.json, pass --start, or write it into ample.toml with ample plan --write.
2. **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 <app-name> --public --format json
   ```
3. **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 <deployment_id> --kind build
   ```

## Tested examples

- **Express basic canary** (tests/deploy-canaries/express-basic): Minimal Express server deployed with the detected npm install / npm run start commands.

## Success checks

- root route responds (`/` on the live URL, expect ample canary express basic)

## 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.
- A missing package-lock.json produces a warning and a slower, non-reproducible install.

## Cost estimate

Estimated 5.00 USD per month (size prices from pricing.toml at build revision a1b8c38919e59cd035ebabaced73cf84ece24371).
- app server x1 `s-1vcpu-1gb`: 5.00 USD

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.

## Verification evidence

- canary_run on 2026-09-19T23:55:33Z at revision `1764076-tls-account-903d345`: Express app with npm install and npm run start deployed on the node-22 template; the public URL served the expected response. (expires 2027-03-18T23:55:33Z)

Last verified: 2026-09-19T23:55:33Z

## Execution binding

MCP tool `ample_deploy` (registry `mcp:ample_deploy`), schema hash `876465fce906da0c` observed 2026-09-20T01:55:48.667900+00:00 at revision `199ff1dfd526`, binding state `current`, required scopes: servers:write.