Designing an SRD

March 9, 2021

Having the majority of my published games being hacks of some sort, I thought it would be interesting to dive into SRDs (system reference documents). What are they? What makes them usable and accessible? The following post is based on my experience as an SRD reader and utiliser.

If you find something I’ve missed or think should be changed/improved, don’t hesitate to send me a message.

What is an SRD?

A System Reference Document is a way to share your game for others to iterate on it. SRDs allow creators to be more intentional in how others interact with your content. I’ve found the core of an SRD to be:

  1. A permission to modify and iterate on your work
  2. The game text that falls under that permission

Permission is usually given in the form of a copyright license.

On licences

This is not legal advice! Copyright law is complicated and I am not a lawyer.

Here’s what I’ve found:


Mörk Borg third party license is an example of clear guidelines on how to properly use its license. Its strength is in the step-by-step approach and straightforward explanation.

Necronautilus has a license integrated into the game. Precise language on what falls under the permission and what doesn’t.

Clarity and extra content

Additionally to the game text itself and a permission, SRDs offer resources for designers to use when hacking and writing for your game. You can use these methods to improve your SRD:

Clear intent. Express who this document is aimed at, what your goals are, etc. It can be helpful to get someone else to look over the text and give feedback.

Clear logo. Something that will visually represent a connection to your game. Completely optional, but useful if your game has a style you want others to use for marketing purposes. You might use a phrase like Compatible with …” to show a link to your game.

Accessibility. Provide a .txt file. It is the most accessible file format for use with screen readers and epub readers.

Way for people to pay for your work. Writing a comprehensive SRD takes effort. I recommend exploring a PWYW (pay what you want) and tip jar options.

Designer commentary. In addition to the game text itself, it is helpful for other designer to understand why and what choices you’ve made. Break down the game text, explain the relationships of those pieces. It will help designers find a way to use and combine parts of the game in a new and exciting way.

Resources. Art, layout files, inspirational links. Anything that makes the process of putting out a game easier.

Great indie SRDs to check out: