## The short version

CDN assets for a Phoenix app on Ample.

---

## WHAT WAS VERIFIED

Verified on Phoenix: a versioned, immutable-cached asset uploaded to a published bucket and served from the CDN URL. Build and start: mix deps.get, MIX_ENV=prod mix compile and mix release in the builder, then the release bin script with PHX_SERVER=true on the elixir-1.18 template; PORT, DATABASE_URL and SECRET_KEY_BASE read in config/runtime.exs.

---

## 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 Phoenix project (mix deps.get, MIX_ENV=prod mix compile and mix release in the builder, then the release bin script with PHX_SERVER=true on the elixir-1.18 template; PORT, DATABASE_URL and SECRET_KEY_BASE read in config/runtime.exs)
- 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. 1

#### Build and start

mix deps.get, MIX_ENV=prod mix compile and mix release in the builder, then the release bin script with PHX_SERVER=true on the elixir-1.18 template; PORT, DATABASE_URL and SECRET_KEY_BASE read in config/runtime.exs; the server must bind 0.0.0.0 on PORT.

2. 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. 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

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

---

## SUCCESS CHECKS

### How to know it worked

- app responds on its public URL (`/` on the live URL, expect ample canary phoenix 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 2026-09-20T23:45:31Z at revision `4d1511e574302f3904b75088bd4048a0975218b3 (CLI 0.1.21)`: Phoenix pattern fixture deployed on Ample (mix deps.get, MIX_ENV=prod mix compile and mix release in the builder, then the release bin script with PHX_SERVER=true on the elixir-1.18 template; PORT, DATABASE_URL and SECRET_KEY_BASE read in config/runtime.exs); for this guide: a versioned, immutable-cached asset uploaded to a published bucket and served from the CDN URL. (expires 2027-03-19T23:45:31Z)

---

## 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 Phoenix (`GET /v1/catalog/nodes/stack%3Aframework-phoenix` 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)

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.

---

## ABOUT THIS RECIPE

### Identifiers and status

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

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

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