# Migrate DigitalOcean Droplet App: Express

Move Express compute from DigitalOcean Droplet 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: Collect the process environment from the droplet (systemd unit, PM2 or supervisor config) into an env file kept out of the repository. Not migrated automatically: Cron jobs, local upload directories and firewall rules are not migrated; move uploads to a bucket and data to a managed database. Cutover: Add the custom domain with `ample domain add`, update DNS from the droplet IP, keep the droplet until verified, then power it off. Rollback: keep the source untouched until you confirm; nothing at the source is changed or deleted by this guide.

## Representative Queries
- Migrate DigitalOcean Droplet 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.

## Prerequisites
- Authorized access to the DigitalOcean Droplet 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

## Infrastructure Requirements
### Compute
- **Status:** verified
- **Summary:** Apps run in isolated x86_64 Firecracker microVMs that auto-pause when idle and wake on request; sizes are the priced VM sizes.

### Postgres
- **Status:** verified
- **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.

## Workflow Steps
1. **Inventory the source**  
   List what DigitalOcean Droplet app provides beyond the component you are moving. Out of scope here: Cron jobs, local upload directories and firewall rules are not migrated; move uploads to a bucket and data to a managed database.

2. **Source step 1**  
   Collect the process environment from the droplet (systemd unit, PM2 or supervisor config) into an env file kept out of the repository.

3. **Source step 2**  
   Replace the droplet's process manager and reverse proxy with the repository's start command; Ample provides HTTPS and supervision.

4. **Source step 3**  
   Inventory what else runs on the droplet: databases, cron, local uploads.

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.
   
   Command: `ample deploy . --name  --public --env-file .env.production`

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 droplet IP, keep the droplet until verified, then power it off.

8. **Rollback**  
   Point DNS or configuration back to the source. The source was never modified; deletion is a separate, user-executed step after validation.

## Success Checks
- destination app responds on its public URL
- configuration-secrets check from the destination example
- relational-records check from the destination example
- data or object counts and checksums match the source

## Limitations
- Documentation only: nothing is executed automatically and no execution binding is offered.
- The source-side procedure is documented from DigitalOcean Droplet 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: Cron jobs, local upload directories and firewall rules are not migrated; move uploads to a bucket and data to a managed database.
- Verified on the node-22 template at s-1vcpu-1gb; region, compliance and request-duration limits are unknown.

## Cost Estimate
- **Currency:** USD
- **Monthly Amount:** 10.0
- **Basis:** size prices from pricing.toml (loaded by the API) at build revision 1ac5595375130d45290090e82ed0f554ccd45405-dirty
- **Components:**
  - **App server**  
    - Size: s-1vcpu-1gb  
    - Monthly Amount: 5.0
  - **Managed PostgreSQL database**  
    - Size: s-1vcpu-1gb  
    - Monthly Amount: 5.0
- **Note:** Destination always-on monthly price of the tested sizes; apps auto-pause when idle. Source costs are unknown to Ample.