### Migrate Railway app: Express

Move Express compute from Railway app to Ample, one component at a time. Destination verified on Ample: the app built, started and answered on its public HTTPS URL with encrypted configuration delivered.  
Source procedure: Export variables from the Railway service (Variables tab or `railway variables`) into an env file kept out of the repository. Not migrated automatically: Railway cron schedules, volumes and private networking are not migrated; persistent data belongs in a managed database, a bucket or an Ample volume.  
Cutover: Add the custom domain with `ample domain add`, update DNS from the Railway target, keep the Railway service until verified, then remove it.  
Rollback: keep the source untouched until you confirm; nothing at the source is changed or deleted by this guide.

#### Representative Queries
- Migrate Railway app: Express
- Where can I host Express built with Express?
- I need a component-scoped export/import or reconfiguration procedure for Express, with compatibility checks, verification and rollback.

#### Resource and Infrastructure Requirements  
- **Resource Requirements:**
  - primitive:compute
  - primitive:postgres  
- **Infrastructure Requirements:**
  1. **Compute** (status: verified)
      - 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** (status: 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
- Authorized access to the Railway app source and its export tooling
- An inventory of every component in scope and out of scope
- A validated backup or copy before any cutover
- An Ample account token with servers:write, databases:read

#### Workflow Steps
1. **Inventory the source**  
   List what Railway app provides beyond the component you are moving. Out of scope here: Railway cron schedules, volumes and private networking are not migrated; persistent data belongs in a managed database, a bucket or an Ample volume.
2. **Source step 1**  
   Export variables from the Railway service (Variables tab or `railway variables`) into an env file kept out of the repository.
3. **Source step 2**  
   Translate `railway.json`/Nixpacks settings into the repository's build and start commands; Ample detects Node and Python builds itself.
4. **Source step 3**  
   Note Railway-only features in use: cron schedules, volumes, private networking, templates.
5. **Deploy on Ample in parallel**  
   `npm install, npm run build --if-present, npm run start` on the node-22 template. Pass the exported variables with --env; keep the source running.
6. **Validate before cutover**  
   Run the app's own checks and, for data, compare counts and checksums; the example checks are the pattern self-tests (/p/configuration-secrets, /p/relational-records).
7. **Cut over**  
   Add the custom domain with `ample domain add`, update DNS from the Railway target, keep the Railway service until verified, then remove it.
8. **Rollback**  
   Point DNS or configuration back to the source. The source was never modified; deletion is a separate, user-executed step after validation.

#### Cost Estimate
- **Currency:** USD  
- **Monthly Amount:** $10.00  
- **Components:**
  - app server (s-1vcpu-1gb) - $5.00/month  
  - managed PostgreSQL database (s-1vcpu-1gb) - $5.00/month  
  - **Note:** Destination always-on monthly price of the tested sizes; apps auto-pause when idle. Source costs are unknown to Ample.

#### Limitations
- Documentation only: nothing is executed automatically and no execution binding is offered.
- The source-side procedure is documented from Railway app's standard tooling and was not executed in this catalog's evidence; the destination side was verified with the pattern fixture.
- No full source-product parity is claimed: Railway cron schedules, volumes and private networking are not migrated; persistent data belongs in a managed database, a bucket or an Ample volume.
- Verified on the node-22 template at s-1vcpu-1gb; region, compliance and request-duration limits are unknown.
- Managed PostgreSQL 16 only; extensions, connection limits and backup or restore procedures on the managed side are not verified beyond the pattern checks.

#### Evidence Summary
- _Destination side verified:_ the Express pattern fixture deployed on Ample (npm install, npm run build --if-present, npm run start on the node-22 template) and its checks passed (the app built, started and answered on its public HTTPS URL with encrypted configuration delivered). The source-side export from Railway app is documented from the vendor's standard tooling and was not executed by this catalog's evidence.

#### Formats
- [HTML Format](/content/migrate/railway-app/express/index.html)  
- [Markdown Format](/content/migrate/railway-app/express.md)  
- [JSON Format](https://api.ample.computer/v1/catalog/recipes/page%3Amigrate%3Arailway-app%3Aexpress)