---
title: "Configure build and start for Express"
description: "Configure build and start for an Express app on Ample."
canonical_url: "https://ample.computer/guides/express/build-and-start"
last_updated: "2026-09-19"
---

# Configure build and start for Express

Canonical URL: https://ample.computer/guides/express/build-and-start
Formats: [HTML](https://ample.computer/guides/express/build-and-start) | [Markdown](https://ample.computer/guides/express/build-and-start.md) | [JSON contract](https://api.ample.computer/v1/catalog/recipes/page%3Aguides%3Aexpress%3Abuild-and-start)
Recipe ID: `page:guides:express:build-and-start` | Revision: `r1` | Catalog revision: `cat_f13ab9a494120b5e`

Status: release `published`, support `verified`, execution `ready`

## 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.

Path: [Agent hosting discovery](/discover/discovery) / [Frameworks and execution targets](/discover/stack) / [Frameworks](/discover/stack/frameworks) / [Express](/discover/stack/framework-express) / [Configure build and start for Express](/guides/express/build-and-start)

## 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)


## Cost estimate

Estimated 5.00 USD per month (size prices from pricing.toml at build revision 515b7316fc6e5a81679407ae0c811146ceb2c5c7).
- 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.

## Input schema

```json
{
  "additionalProperties": false,
  "properties": {
    "name": {
      "description": "App name (lowercase, digits and dashes)",
      "maxLength": 63,
      "minLength": 1,
      "pattern": "^[a-z0-9-]+$",
      "type": "string"
    },
    "path": {
      "description": "Project directory to deploy, or one service name from ample.toml",
      "maxLength": 512,
      "minLength": 1,
      "type": "string"
    },
    "size": {
      "description": "VM size; omit to let Ample pick a runtime-safe size",
      "enum": [
        "s-1vcpu-256mb",
        "s-1vcpu-1gb",
        "s-1vcpu-2gb",
        "s-2vcpu-2gb",
        "s-2vcpu-4gb"
      ],
      "type": "string"
    },
    "start": {
      "description": "Start command override when package.json has no start script",
      "maxLength": 512,
      "type": "string"
    }
  },
  "required": [
    "name",
    "path"
  ],
  "type": "object"
}
```

## Next actions

- Browse the catalog index (GET /v1/catalog on the api origin; auth: false, approval: false)
- Search published recipes by intent, stack and constraints (POST /v1/catalog/search on the api origin; auth: false, approval: false)
- Prepare a side-effect-free deployment plan for an authorized project (POST /v1/catalog/plan on the api origin; auth: true, approval: false)
- Read the existing agent authentication setup (GET /mcp/setup on the api origin; auth: false, approval: false)
- Browse Express (GET /v1/catalog/nodes/stack%3Aframework-express on the api origin; auth: false, approval: false)
- Browse Configure deployment (GET /v1/catalog/nodes/intent%3Aconfigure-deployment on the api origin; auth: false, approval: false)
- Browse Public web service (GET /v1/catalog/nodes/pattern%3Apublic-web-service on the api origin; auth: false, approval: false)

Actions describe possible next steps. They are typed data, not commands, and grant no permission.