Migrate Vercel app: FastAPI | Ample

INFRASTRUCTURE

What it needs

PREREQUISITES

Before you start

TESTED CONFIGURATION

Exactly what was tested

STEP BY STEP

How to do it

  1. Inventory the source

List what Vercel app provides beyond the component you are moving. Out of scope here: Edge middleware, ISR revalidation, image optimization, cron jobs and Vercel integrations are not migrated and are unverified on Ample.

  1. Source step 1

Copy environment variables from the Vercel project settings (or vercel env pull) into an env file you keep out of the repository

  1. Source step 2

Note the framework preset, build command and output directory; Ample detects the same from the repository

  1. Source step 3

List Vercel-only features in use: edge middleware, ISR revalidation, image optimization, cron jobs, integrations

  1. Deploy on Ample in parallel

pip install into .ample/python from requirements.txt, then uvicorn from run.py reading PORT on the python-3.12 template. Pass the exported variables with --env; keep the source running.

    ample deploy . --name <app-name> --public --start "python3 run.py" --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`, set the documented DNS records, keep the Vercel deployment until traffic is verified, then remove the domain from Vercel.

8.  Rollback

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

## EXAMPLES

### Tested examples

- **FastAPI pattern fixture (destination)** (`tests/deploy-canaries/fastapi-patterns`): Verified destination basis: FastAPI compute.

## SUCCESS CHECKS

### How to know it worked

- destination app responds on its public URL (`/` on the live URL, expect ample canary fastapi patterns)
- configuration-secrets check from the destination example (`/p/configuration-secrets` on the live URL, expect see the pattern fixture checks)
- relational-records check from the destination example (`/p/relational-records` on the live URL, expect see the pattern fixture checks)
- data or object counts and checksums match the source

## LIMITATIONS

### Know the limits

- Documentation only: nothing is executed automatically and no execution binding is offered.
- The source-side procedure is documented from Vercel 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: Edge middleware, ISR revalidation, image optimization, cron jobs and Vercel integrations are not migrated and are unverified on Ample.
- Verified on the python-3.12 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.

## COST

### Cost estimate

Estimated 10.00 USD per month (size prices from pricing.toml at build revision a1b8c38919e59cd035ebabaced73cf84ece24371).

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

Destination always-on monthly price of the tested sizes; apps auto-pause when idle. Source costs are unknown to Ample.

## EVIDENCE

### Verification evidence

- canary_run on 2026-09-21T01:14:18Z at revision `50dbac567d2c5cc8e55e6c748a646be0025d9cfb-dirty (CLI 0.1.21)`: Destination side verified: the FastAPI pattern fixture deployed on Ample (pip install into .ample/python from requirements.txt, then uvicorn from run.py reading PORT on the python-3.12 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 Vercel app is documented from the vendor's standard tooling and was not executed by this catalog's evidence. (expires 2027-03-20T01:14:18Z)

## EXECUTION

### Execution binding

No execution binding. This recipe is documentation only; nothing is executed automatically.

## NEXT ACTIONS

### Typed next actions

- Browse the catalog index (`GET /v1/catalog` on the api origin; authentication not required, approval not required)
- Search published recipes by intent, stack and constraints (`POST /v1/catalog/search` on the api origin; authentication not required, approval not required)
- Prepare a side-effect-free deployment plan for an authorized project (`POST /v1/catalog/plan` on the api origin; authentication required, approval not required)
- Read the existing agent authentication setup (`GET /mcp/setup` on the api origin; authentication not required, approval not required)
- Browse Vercel app (`GET /v1/catalog/nodes/migration%3Avercel-app` on the api origin; authentication not required, approval not required)
- Browse FastAPI (`GET /v1/catalog/nodes/stack%3Aframework-fastapi` on the api origin; authentication not required, approval not required)
- Browse Migrate compute (`GET /v1/catalog/nodes/intent%3Amigrate-compute` on the api origin; authentication not required, approval not required)

Actions describe possible next steps. They are typed data, not commands, and grant no permission. Public discovery never provisions anything; planning requires your own authenticated token and approval happens in your client.