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Gemfast is a fast and secure rubygems server written in Go. That means it can be compiled into a single binary file and work on linux, darwin and windows operating systems. Gemfast can be quickly installed on a server without any other dependencies and configured using a single HashiCorp Configuration Language (HCL) file.

Why Gemfast

Gemfast was created for users who need to self-host their rubygems and want something quick to setup and easy to manage. Gemfast allows users to mirror and cache gems from as well as upload their own internally developed gems which can't be distributed publically. It supports both the legacy Dependency API and the newer Compact Index API.

Gemfast has the following unique benefits:

  • Two installation methods: Debian Package and Docker Image
  • No need to install/upgrade/manage a version of Ruby on the server
  • No external server dependencies like postgres, redis or memcached
  • Automatic HTTPS via Caddy
  • User login via GitHub oAuth
  • No external server dependencies like postgres, redis or memcached
  • Allow/Deny gems based on CVE severity or a regex list using the ruby-advisory-db
  • Go is generally faster and requires less memory then Ruby (still ❤️ Ruby though)


Gemfast is currently distributed in two different ways, a .deb package and a docker image.

The .deb package includes a web server which proxies HTTPS traffic to Gemfast and is recommended when installing Gemfast on a virtual machine or bare-metal instance.

Debian Package

To install the .deb package, download it from the latest GitHub release and install it with dpkg.

curl -L -O gemfast_<version>_amd64.deb
sudo dpkg -i ./gemfast_<version>_amd64.deb
sudo systemctl start gemfast.service

Debian Package SSL

The Gemfast .deb package includes Caddy Server which will automatically generate and manage a let's encrypt SSL certificate for your server. Caddy offers a few ways to generate a valid SSL certificate, see: If the let's encrypt challenge fails, the server will use a self-signed certificate.


When running Gemfast as a container, its important to mount the following directories:

  • /etc/gemfast - The directory for the gemfast.hcl config file
  • /var/gemfast - The directory for the Gemfast data including gems and database
docker run -d --name gemfast-server \
  -p 2020:2020 \
  -v /etc/gemfast:/etc/gemfast \
  -v /var/gemfast:/var/gemfast \

Building From Source

Gemfast uses Make to build binaries. To build and run a static binary:



You can configure gemfast settings using the /etc/gemfast/gemfast.hcl file. There are many options all of which are listed in the documentation.

For more information see:


🚧 The UI feature is currently under construction and is considered experimental 🚧

Dashboard UI

Gemfast includes a basic ui which is accessible from my.server.url/ui. For example, running it locally you can access it at http://localhost:2020/ui.

The ui currently supports viewing and searching gems from both the private gems namespace and gems that have been cached from an upsteam.

You can also disable the ui in /etc/gemfast/gemfast.hcl:

ui_disabled = true


Gemfast is open source software licensed under the Apache 2.0 License.

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
See the License for the specific language governing permissions and
limitations under the License..