# Configure environment and secrets for Phoenix

## Summary

Configuration and secrets for a Phoenix app on Ample. Verified on Phoenix: an --env value delivered encrypted and reported as present without being echoed (secret=set). 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 requirements

- [Compute](/content/discover/primitive/compute/index.html): verified (Apps run in isolated x86_64 Firecracker microVMs that auto-pause when idle and wake on request; sizes are the priced VM sizes.)

## Prerequisites

- 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)
- An Ample account token with servers:write

## Exact tested configuration

- template: `elixir-1.18`
- runtime: `elixir`
- size: `s-1vcpu-1gb`
- install: `mix local.hex --force && mix local.rebar --force && MIX_ENV=prod mix deps.get --only prod`
- build: `MIX_ENV=prod mix compile && MIX_ENV=prod mix release --overwrite`
- start: `PHX_SERVER=true _build/prod/rel/$(ls _build/prod/rel | head -n 1)/bin/$(ls _build/prod/rel | head -n 1) start`

## Steps

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. **Pass values on deploy.** Use --env KEY=value (repeatable) or --env-file; values are encrypted at rest and reused on redeploys. Declare names only in ample.toml.

```
    ample deploy . --name <app-name> --public --env MY_SECRET=...
    ```
3. **Verify.** Fetch the live URL and /p/configuration-secrets on the example; on failure read the build and runtime logs.

```
    ample logs <deployment_id> --kind build
    ```

## Tested examples

- **Phoenix pattern fixture** (tests/deploy-canaries/phoenix-patterns): Verified configuration and secrets on Phoenix.

## Success checks

- app responds on its public URL (`/` on the live URL, expect ample canary phoenix patterns)
- configuration-secrets check from the example (`/p/configuration-secrets` on the live URL, expect see the pattern fixture checks)

## Limitations

- Verified on the elixir-1.18 template at s-1vcpu-1gb; other sizes and Phoenix major versions are not verified.
- Region, compliance attestations and request-duration limits are unknown and not claimed.

## Cost estimate

Estimated 5.00 USD per month (size prices from pricing.toml at build revision a1b8c38919e59cd035ebabaced73cf84ece24371).
- app server x1 `s-1vcpu-1gb`: 5.00 USD

Always-on monthly price of the tested sizes; apps auto-pause when idle. Buckets are allocation-priced per quota and not included.

## Verification evidence

- canary_run on 2026-09-20T23:45:31Z at revision `4d1511e574302f3904b75088bd4048a0975218b3-dirty (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: an --env value delivered encrypted and reported as present without being echoed (secret=set). (expires 2027-03-19T23:45:31Z)