## The short version

To deploy a Sinatra 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 `ruby-3.4` template, starts it with `bundle exec rackup -o 0.0.0.0 -p $PORT` and returns a public HTTPS URL.

## Deploy Sinatra

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](/content/agents/index.html).

```bash
curl -fsSL https://get.ample.computer/install.sh | sh
ample auth signup
# then, in your agent:
# "Deploy this Sinatra 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.

```bash
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.

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

## What Ample runs

| Template | `ruby-3.4` |
| Install | `bundle config set --local path vendor/bundle && bundle config set --local without 'development test' && bundle install` |
| Start | `bundle exec rackup -o 0.0.0.0 -p $PORT` |
| Tested size | `s-1vcpu-1gb` |

Verified on Sinatra: the app built and started with the documented commands and answered on its public HTTPS URL. Build and start: bundle install into vendor/bundle from Gemfile.lock (development and test groups skipped), then Puma via `rackup` (config.ru) reading PORT on the ruby-3.4 template.

Last verification (September 20, 2026): Sinatra pattern fixture deployed on Ample (bundle install into vendor/bundle from Gemfile.lock (development and test groups skipped), then Puma via `rackup` (config.ru) reading PORT on the ruby-3.4 template); 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 Sinatra project (bundle install into vendor/bundle from Gemfile.lock (development and test groups skipped), then Puma via `rackup` (config.ru) reading PORT on the ruby-3.4 template)
- An Ample account token with servers:write

### Know the limits

- Verified on the ruby-3.4 template at s-1vcpu-1gb; other sizes and Sinatra major versions are not verified.

## Frequently asked questions

### Do I need a Dockerfile to deploy Sinatra?

No. Ample detects Sinatra from the repository and builds it from source on the `ruby-3.4` template. Dockerfile build steps are not run.

### How do I add a database to a Sinatra 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 Sinatra](/content/guides/sinatra/database-connection/index.html).

### What does it cost to host a Sinatra 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](/content/pricing/index.html).

### 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 Sinatra](/content/guides/sinatra/deployment-diagnostics/index.html).