Supported technologies for the Ruby agent

We support the following technologies for this agent.


Supported versions


Language version

  • 2.7.X: First supported agent was 3.8.0

  • 2.6.X: First supported agent was 2.3.0

  • 2.5.X: First supported agent was 2.0.0

See the Ruby Maintenance Branches schedule for specific release dates.

Contrast supports Ruby Long-Term Support (LTS) versions in normal maintenance and security maintenance status. Contrast shifts its support for Ruby versions as the working group shifts its LTS windows.

Not supported:

  • 2.4.X: Last supported agent was 3.9.1

Operating systems

  • 64-bit OSX

  • 64-bit Linux

  • 64-bit Alpine

Starting with agent version 3.0.0, the gem installation step requires the compilation of C extensions. This process is automatic, but you may need to install the following in the target environment:

  • gcc, make, automake and autoconf (Package names may vary. You may install your platform's version of build-essential.

  • system headers

The agent runs in the Ruby application layer with some C dependencies so it may need to be installed with the --platform ruby flag to allow for compilation in either g libc or musl libc based systems.

Application frameworks

While the agent can still run on Rack-based web frameworks that aren't officially supported, Contrast may produce less-specific findings than it does for supported frameworks. Instead of reporting that a vulnerability occurs in your application code, Contrast may report it within the framework code where it interfaces directly with the Rack methods.


Contrast doesn't support old or deprecated versions of third-party modules.

Testing environments

We test on a matrix of our supported Operating Systems, Application Frameworks, and Web Servers and also run the Ruby Mspec Suite.

When changes are made, Contrast runs a battery of automated tests to ensure that it detects findings in supported technologies across all supported versions of Ruby. In addition to its own testing, Contrast also runs the Ruby Spec Suite against an environment with the agent enabled.

Web servers