How to deploy a Phoenix app | Ample

The short version

To deploy a Phoenix app on Ample, run ample deploy . --name <app-name> --public in the project directory, or ask your coding agent to deploy it to Ample. Ample builds it on the elixir-1.18 template, runs the tested start command below and returns a public HTTPS URL.

Deploy Phoenix

1. 1

Ask your coding agent

Install the Ample CLI and create an account (no browser or card needed), then ask Claude Code, Codex, Cursor or any agent with a shell to deploy the project. See Ample for coding agents.

curl -fsSL https://get.ample.computer/install.sh | sh
ample auth signup
# then, in your agent:
# "Deploy this Phoenix app to Ample"

2. 2

Or deploy from the CLI

Run the deploy once from the project directory. It waits until the app is live or failed and prints the URL; exit 0 is live, 1 failed, 2 needs input.

ample deploy . --name <app-name> --public

3. 3

Or use MCP

Agents connected to the Ample MCP server (https://api.ample.computer/mcp, or ample mcp over stdio) call ample_deploy with the same arguments.

4. 4

Verify

Open the URL. If the deploy failed, read the build log, then the runtime log, fix the cause and deploy again.

ample logs <deployment_id> --kind build

What Ample runs

| Template | elixir-1.18 | | 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 | | Tested size | s-1vcpu-1gb |

Verified on Phoenix: the app built and started with the documented commands and answered on its public HTTPS 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.

Last verification (September 20, 2026): 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: the app built and started with the documented commands and answered on its public HTTPS URL.

Before you deploy

You need

• 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

Know the limits

• Verified on the elixir-1.18 template at s-1vcpu-1gb; other sizes and Phoenix major versions are not verified.

Frequently asked questions

Do I need a Dockerfile to deploy Phoenix?

No. Ample detects Phoenix from the repository and builds it from source on the elixir-1.18 template. Dockerfile build steps are not run.

How do I add a database to a Phoenix app?

Leave DATABASE_URL unset and deploy: when the code needs Postgres, MySQL, Redis or MongoDB, Ample creates a managed database and passes its connection string to the app. See Connect Postgres for Phoenix.

What does it cost to host a Phoenix app on Ample?

The Free plan runs 2 apps at once with no card and a hard monthly budget, so it never bills you. Larger needs are priced on volume; see pricing.

What if the deploy fails?

ample deploy waits until the app is live or failed. A failure returns who must act, a diagnosis and a suggested fix; read the logs with ample logs <deployment_id> --kind build. See Diagnose deployment failures for Phoenix.