## The short version

CDN assets for a FastAPI app on Ample.

## WHAT WAS VERIFIED

Verified on FastAPI: a versioned, immutable-cached asset uploaded to a published bucket and served from the CDN URL. Build and start: pip install into .ample/python from requirements.txt, then uvicorn from run.py reading PORT on the python-3.12 template.

## INFRASTRUCTURE

## What it needs

- [Compute](/content/discover/primitive/compute/index.html): verified (Apps run in isolated x86\_64 Firecracker microVMs; sizes are the priced VM sizes.)
- [CDN](/content/discover/primitive/cdn/index.html): verified (A published bucket's objects are served at its public\_url. It does not front app compute and is not a cache or key-value store.)

## PREREQUISITES

## Before you start

- A FastAPI project (pip install into .ample/python from requirements.txt, then uvicorn from run.py reading PORT on the python-3.12 template)
- A bucket from `ample bucket create` with credentials passed as encrypted S3\_* environment variables
- An Ample account token with servers:write, buckets:read

## STEP BY STEP

## How to do it

1. **Build and start**  
   pip install into .ample/python from requirements.txt, then uvicorn from run.py reading PORT on the python-3.12 template; the server must bind 0.0.0.0 on PORT.

2. **Publish a bucket for public assets**  
   Publish only the asset bucket; upload versioned keys with an immutable Cache-Control header and build URLs from its public URL.  
   
   ```  
   ample bucket publish <bucket-name>  
   ```

3. **Verify**  
   Fetch the live URL and /p/versioned-static-assets on the example; on failure read the build and runtime logs.  
   
   ```  
   ample logs <deployment_id> --kind build  
   ```

## EXAMPLES

## Tested examples

- **FastAPI pattern fixture** (`tests/deploy-canaries/fastapi-patterns`): Verified CDN assets on FastAPI.

## SUCCESS CHECKS

## How to know it worked

- app responds on its public URL (`/` on the live URL, expect ample canary fastapi patterns)
- versioned-static-assets check from the example (`/p/versioned-static-assets` on the live URL, expect see the pattern fixture checks)

## COST

## Cost estimate

Estimated 5.00 USD per month (size prices from pricing.toml at build revision ca0b484a7a9957c573a88d3a32dc603c3c10135a).

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

Upper-bound monthly price of the tested sizes. Buckets are allocation-priced per quota and not included.

## EVIDENCE

## Verification evidence

- canary\_run on 2026-09-21T01:14:18Z at revision `50dbac567d2c5cc8e55e6c748a646be0025d9cfb (CLI 0.1.21)`: 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); for this guide: a versioned, immutable-cached asset uploaded to a published bucket and served from the CDN URL. (expires 2027-03-20T01:14:18Z)

## EXECUTION

## Execution binding

MCP tool `ample_deploy` (registry `mcp:ample_deploy`), schema hash `876465fce906da0c` observed 2026-09-22T00:31:22.774679+00:00 at revision `e6446ceea69b`. Binding state at export: schema\_changed. Required scopes: servers:write, buckets:read.

## 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 FastAPI (`GET /v1/catalog/nodes/stack%3Aframework-fastapi` on the api origin; authentication not required, approval not required)
- Browse Add CDN (`GET /v1/catalog/nodes/intent%3Aadd-cdn` on the api origin; authentication not required, approval not required)
- Browse Versioned static assets (`GET /v1/catalog/nodes/pattern%3Aversioned-static-assets` on the api origin; authentication not required, approval not required)

## ABOUT THIS RECIPE

## Identifiers and status

Recipe `page:guides:fastapi:cdn-assets`. Revision r1.

release **published** support **verified** execution **blocked (schema\_changed: live tool schema differs from the recorded binding)**

Formats: [HTML](/content/guides/fastapi/cdn-assets/index.html) 
| [Markdown](/content/guides/fastapi/cdn-assets.md) 
| [JSON contract](https://api.ample.computer/v1/catalog/recipes/page%3Aguides%3Afastapi%3Acdn-assets)