This is a brief introduction to the HearthSim GUI.

There is now a web version of HearthSim GUI at hearthsim.io. It uses HearthSim as the backend and is more frequently update to the latest versions. Check it out!

Current version is v0.6, based on commit 62a44be040f72b095f851c17fd48ae5feb258c55.


Special thanks to Kallin and MrHen for all the great contributions!


v0.6 — December 29, 2014:

  • Significant optimization to the simulation engine. Simulations should be faster by a factor of a few.
  • Implemented a bunch of more cards
  • Updated cards for Goblins and Gnomes
  • Various bug fixes

v0.5.1 — November 27, 2014:

  • Bug fix to Soulfire

v0.5 — November 18, 2014:

  • About 30 more cards implemented
  • Significant changes to the underlying simulation engine — this will hopefully speed up the development.


  • Fixed a bug where using Defender of Argus crashed the game under certain conditions.


  • Optimization to the simulation engine
  • 200 cards implemented
  • Updated for the latest patch (patch 6485)


  • All heroes are now implemented and selectable from the deck creation view
  • A bunch of new cards implemented
  • A bunch of memory usage optimization to try to reduce the memory usage


  • A bunch of new cards implemented
  • Updated plots for better looking visuals


  • Initial release

Note that the OS X app bundle includes a bundled JRE.


To load a create a deck:

To load a deck, click on the “Load…” button of the respective player. The format of the deck file is described here.

To create or modify a deck, click on the bars icon at the top of the card list. It will open a list of available cards in the center panel. To add cards to the deck, click on the cards in the center panel. To remove a card from the deck, click on the card in the deck. Click on the bars icon to close the card selection panel.

Note: Saving the deck list is not currently implemented.


General simulation settings can be changed by clicking on the “Settings…” button in the center panel.

Note: Please be careful with the “Number of threads” option. HearthSim’s memory usage will scale linearly with the number of threads. Going above 4 threads will typically make the simulation run out of memory.


Simply hit the “Run” button. Please note that the stop button currently does not work.

Discussions and Questions

Head over to the discussion forums at Versify: All Things Hearthstone, in particular the HearthSim and HearthSim-dev boards. I’m always interested in new how HearthSim works and any new ideas you might have!

4 thoughts on “HearthSim

  1. DarkmindBR

    Hi, thank you sir for this nice work. I’d like to ask if there’s a way to add my own fan-made cards based (of course) on currently hearthstone’s mechanics.

    1. oyachai Post author

      There’s no easy way to do that currently. It’s something I’ll look to implement in the near future.

  2. qingjie

    Hi , I am a hearthstone player , I think it this is a great and interesting work . I have build a deck , run the simulation , I find the result is baiscly right ,But I want to see the details of the each game for deeply rearch .So my question is how can I get the log of the game, including each move by AI?


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