What is Kamal used for?

Kamal deploys containerized web apps to bare metal or cloud servers over SSH with zero-downtime switching between containers. It is a good fit for deploying Rails apps to your own servers and moving off hosted platforms to plain VMs.

Is Kamal open source?

Yes. Kamal is open source under the MIT licence. Its source code is on GitHub at basecamp/kamal and is written mainly in Ruby.

Yes. Kamal is open source, so the software itself is free to use.

What is Kamal an alternative to?

Kamal is an open-source alternative to Heroku, Render, Octopus Deploy and Fly.io. Other open-source alternatives to Heroku include Coolify, Dokploy and Dokku.

Is Kamal actively maintained?

Yes. The most recent commit to Kamal was on 30 September 2026, and the latest release is v2.12.0, published on 18 June 2026. The project has 15k stars on GitHub.

Kamal: open-source alternative to Heroku, Render

About Kamal

Kamal is a deployment tool for web applications that can run anywhere, from bare metal servers to cloud virtual machines. It uses a proxy component called kamal-proxy to switch requests between containers without downtime, and it works across multiple servers by running commands over SSH using SSHKit.

Originally built for Rails applications, Kamal works with any web app that can be packaged in a Docker container. Documentation on installation, configuration and commands is on kamal-deploy.org, and the documentation itself lives in a separate repository where improvements are welcome.

Kamal is written in Ruby, developed by Basecamp, and released under the MIT license. Because it deploys to servers you control, it suits teams who want a simple alternative to hosted platforms while still getting rolling, zero-downtime releases.

Key features

Zero-downtime container switching
Deploys to bare metal or cloud VMs
Multi-server deployments over SSH
Works with any Dockerized web app
kamal-proxy request routing

Good fit for

→Deploying Rails apps to your own servers
→Moving off hosted platforms to plain VMs

Built with: Ruby
Tags: deployment; docker; ruby; rails; devops; zero-downtime; ssh; self-hosted

Kamal: questions and answers

What is Kamal used for?: Kamal deploys containerized web apps to bare metal or cloud servers over SSH with zero-downtime switching between containers. It is a good fit for deploying Rails apps to your own servers and moving off hosted platforms to plain VMs.
Is Kamal open source?: Yes. Kamal is open source under the MIT licence. Its source code is on GitHub at basecamp/kamal and is written mainly in Ruby.
Is Kamal free?: Yes. Kamal is open source, so the software itself is free to use.
What is Kamal an alternative to?: Kamal is an open-source alternative to Heroku, Render, Octopus Deploy and Fly.io. Other open-source alternatives to Heroku include Coolify, Dokploy and Dokku.
Is Kamal actively maintained?: Yes. The most recent commit to Kamal was on 30 September 2026, and the latest release is v2.12.0, published on 18 June 2026. The project has 15k stars on GitHub.