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Working on CleanSlate themes locally

Anyone who wants to build CleanSlate themes should check out the Hammer Virtual Machine. Its source, installation, and documentation instructions are on Github. We also have two videos on how to install Hammer VM and how to use it to work on CleanSlate themes locally.

hammer boot up screen


Hammer is a theme development tool for the CleanSlate CMS template rendering engine. Hammer was created to help you iterate quickly on themes and template markup.

Hammer is not for content creation. Content creation should be done in production at

Hammer is similar to Mock Builder for SlateCMS, but has many differences due to the different architecture of CleanSlate. If you are familiar with Mock Builder you should be able to quickly get up and running with Hammer.

Where CAN I get hammer?

To install Hammer on your system we recommend installing the  Hammer Virtual Machine.

CleanSlate Theme Development Tutorial Series
Video #14 Part 1: Hammer VM install

Curious how Hammer works?  The source code is available on Github:

The wiki documentation on Github will help you get started using Hammer.

As of March 2021, Liquid in CleanSlate does not have a local development environment available. Hammer VM will only work with the Radius templating language.

We're currently exploring options and writing code to make a local development environment available for Liquid. Stay tuned.

Last updated on July 20, 2022.

We welcome all questions, feedback and bug reports. If you're having an issue, we usually need the following information:

  • A brief description of the issue
  • A link to the page where you saw the issue
  • Screenshots that illustrate the problem - How do I take a screenshot?

Kindly email for help or use the form on the request help page.