HeroMuster Open Legend API


The HeroMuster Open Legend API gives you read access to content created or formatted through the site. This includes:

  • Character Builder
  • NPC Generator
  • Core Elements (e.g. Feats, Banes, Boons, etc)


Currently, the API does not allow you to change data stored on HeroMuster. Secondarily, it also does not restrict requests based on users or rate limits. This is subject to change in the future if it becomes abused. Be responsible with your code and do not create programmatic mutli-threaded requests.


Version Number: 1.0.0
Last Updated: October 8, 2017.


There are no authentication requirements at this time.

Response Format

The response to every request is sent in JSON format. All requests contain a meta key containing three elements:

  1. query: The API request that begins with /api/ followed by the rest of the query.
  2. time: The amount of time it took for the query to be executed (in seconds).
  3. status: Either success or error. This informs the content of the other first tier key.

There is also one more key included, either success or error, matching the 3rd result in meta. This contains the main error message or results for your API request.

The value of the error key will be a plain-text explanation of what went wrong with your request.


For Open Legend RPG tabletop roleplayers, a collection of tools to help GMs and players. Character builder, item builder, NPC generator, and more.