Tag Archives: tool

Deck Simulator for Hearthstone 1.3 released (more cards)!

I’m very pleased to announce that version 1.3 of Deck Simulator for Hearthstone iPad app has been released on the Apple App store.

Since I’ve released this app I’ve gotten feedback from several people that there needs to be more cards added to fill out the entire set of Hearthstone cards. Adding cards is a time consuming process but I decided to focus on this for this release. I’ve added all Shaman-class cards as well as all Naxxramas cards, around ~50 new cards for a total of 366 in the database.  Though there are still some cards missing, this brings the percentage of total cards much higher and should make it a much more productive tool.

The Naxxramas cards are especially important since they can involve a lot of work to get hold in the actual game. With this app,  you can play around with the cards you haven’t had a chance to acquire yet.

Besides the new cards I’ve also fixed a bug which made the Planner AI weak in certain cases, and also added card level statistics which appear at the end of each simulation and give important information such as average amount of damage dealt by each card. I’ll write up on a post on this feature soon.

Here is the app’s page on iTunes:


You can also search for it in the app store with the keywords “Hearthstone Deck Simulator”  (without quotes).


Deck Simulator for Hearthstone V1.2 Released on Apple App Store!

I’m very happy to announce Deck Simulator for Hearthstone‘s 3rd version (1.2) is now available on the Apple App store!

For this release I decided to take a break from adding new cards and focus on adding a few features that will make the tool easier to use and more productive.

For example, I’ve added a very cool feature that allows you to evaluate to what extent each card in a deck is contributing to it’s overall strength, and also added a rating system for decks to easily compare them (HELO = Hearthstone ELO).

For full details of the release please see the app’s page here:


The app is currently completely free, with no ads, though will only be this way for a limited time.

I’ll be writing some more posts in the feature highlighting some of these new features and discussing how to use them.

Decks included in the simulator’s database and deck evolution

The Deck Simulator for Hearthstone app includes a database of decks that are intended to be used as comparison points against decks you make, with the goal of classifying their strength. These were mostly made by myself, my friends, or from decks I picked up online somewhere. However three of the decks included were designed with the help of an evolutionary algorithm that I created:

  • Evolved Paladin 205
  • Evolved Paladin 215
  • Evolved Warrior

Describing the entire algorithm in detail would be be quite lengthy, so for now I’ll just describe it briefly from a high level:

1) Create a bunch of decks with random cards

2) Play a single-elimanation tournament until the winner is decided, and rank the decks by their win rate

3) Get rid of the lower-ranking decks and replace them with mutated versions of the higher-ranking decks. For example I might remove or replace a random card or two

4) Go back to step #2

After going through the process through hundred of iterations (tournaments), if things went well the winning decks should be quite strong. It took a lot of trial and error and parameter tweaking, but eventually I ‘evolved’ a few decks that weren’t so bad. The above three are some of the better ones from that group.

I’m not going to give the full deck lists here, but if you are curious please consider downloading the app on iTunes . I will say that their crafting cost isn’t cheap (two of the decks are over 9000). Also it’s interesting that all three of them just happen to have Ragnaros the Firelord (one of my favorite cards).

I haven’t tried any of these decks in real games online, but if you happen to own the cards feel free to try them out and let me know how they perform.



Hearthstone Simulator’s game modes

In version 1.0 of Deck Simulator for Hearthstone, there are four different simulation modes.  In this article I’ll give a description of each with some related information to help you use them more effectively.

All play first

In this mode,  each participant will be matched against the participant that is listed first in the participants table. For example if you have four participants A, B, C, and D, you will have the following matchups (or pairings):

A vs B, A vs C, A vs D

Each matchup will play a number games equal to the “Matches per pairing” setting on the Configure Simulation screen.

All play all

In this mode, each participant will be matched up against all other participants (except for itself). So continuing with the same example with 4 participants, the following matchups will be used:

A vs B, A vs C, A vs D, B vs C, B vs D, C vs D

You may have noticed that “B vs A” is not listed here – that is because when two participants play a game, the order of who goes first is randomly chosen, so “B vs A” represents the same thing as “A vs B”.

Just as in “All play first” mode, the “Matches per pairing” setting is used to decide the number of games per matchup or pairing.


This mode simulates a single elimination tournament. To keep things simple it requires a number of players that is a power of 2 (ex: 2, 4, 8, 16, etc.). Using the same 4 player example, there is two matchups created (for example A vs B and C vs D) and each is played “Matches per pairing” times. Then the winner of each of those sets of matches moves on to  the next round, so if A and D won the most matches, they would play each other (A vs D). Finally, the winner of that set of matches would be the total winner.

This is the only mode where the total number of games played by each participant is different, and that is why the number is listed on the simulation screen next to each participant. Furthermore, the ranking isn’t just based on wins since a participant could have a great win rate until a certain matchup where things went sour. Rather, the participants are ranked by the number of total matches played and then their win rate.


This is the simplest game type where two participants is required, no more or no less. The participants play each other a single time (“Matches per pairing” is not used).

The main reason for this match type is a detailed log of the entire game is shown on the simulation screen. If you want to see how the AIs are playing your decks you can follow the entire game via this.

(The reason a full log is not shown for other game types is that it would slow the game down too much.)


So how to choose what mode to use? Here is a quick guide:

1. When you are trying to test whether one or more decks can beat a specific deck, use “All play one” mode.

2. When you want a thorough analysis of how good a deck is vs a bunch of other decks, use “All play all” mode. Keep in mind the number of total games goes up (roughly) exponentially as you add more players, so using this mode for a large number of decks could take a long time, depending not he number of matches per pairing.

3. When you want to get a rough feeling for the ranking of a large number of decks, use “Tournament” mode.

4. When you want to see the play-by-play action to verify the AI or get some pointers for your own play, use “Single” mode.


Why create a Hearthstone Simulator? The story behind why.

Before I spend time talking about how the simulator works and how to use it effectively, I’d like to give a little history as to why I was motivated to create it in the first place.

A few months back, I was pretty into Hearthstone and trying to figure out how to adjust my decks to perform better, and how to build good decks from scratch. I knew some of the basics of deck construction (like a proper mana curve and trying to choose cards that compliment one another), but actually putting that into practice was tricky.

More than that, the bigger problem was that actually testing any of my deck-building ideas took so much time. I had to first decide what cards I wanted, then win enough games to buy cards, dust the ones I didn’t need, and then make the cards I wanted. Then I had to play several games with real opponents to get a feel for whether the deck was any good.

To top things off, since the ladder system in Hearthstone adjusts to your wins and losses, it’s hard to get a real absolute measure of your deck’s strength. For example, if you loose enough games you’ll eventually be put against players who have bad deck-making skills and bad tactics. Just because you win those games, it doesn’t mean your deck is any good.

So one day I thought to myself – what if I could estimate whether one deck was better than an other by using a simulator that mimicked the rules of game? 

One reason I enjoyed and immediately got addicted to Hearthstone was that it was quite similar to Magic: The Gathering, which is a (physical) collectable card game that has managed to maintain some level of popularity since its creation in 1993. While it shares some of the basic concepts with Hearthstone, such as ‘mana’, ‘spells’ and ‘creatures’ (equivalent to Hearthstone ‘minions’), the rules are greatly simplified. For example, Hearthstone doesn’t contain any ‘land’ type cards and minion cards’s effects cannot be activated at will. In fact, except for secrets, there is no way the other play can interject in the middle of your turn. This makes the number of possibilities, and number of rules drastically simpler in Hearthstone, and was one of the reasons I thought making a computerized simulation was even possible.

Another reason I decided to actually attempt to build such a simulation was because a little searching around on the net didn’t show any similar apps or websites out there. There are a bunch of ‘deck managers’ and ‘Arena simulators’ but I never came across anything that actually simulated the game play-by-play. (After trying to develop one myself I finally figured out why – It’s quite a challenging task!)

I’ve always been into simulations since I was younger so I decided to put that passion, some coding skills, and my interest in Hearthstone into something that I hoped would turn out to be a lot of fun.

I think I’ll leave it at this for today, but please be sure to check out Deck Simulator for Hearthstone on the Apple App store!


Deck Simulator for Hearthstone: accepted to Apple App Store!!!

After a long period of expectant waiting, I’m very happy to announce that Deck Simulator For Hearthstone has been accepted by Apple and is now available in the Apple Store! I came into the process expecting to be in the review queue for around 6 to 7 days, but the actual wait was closer to two weeks. Fortunately, once the app got into the review process things went smoothly from there, and it was accepted without any issues.

This was our first app and we weren’t sure what to expect, but it was overall a great learning experience.

If you want to find it easily, you can do a quick search for Hearthstone and it should come up in the top ten results (it was #7 when I did a few minutes ago). You can recognize it easily by the blue and green icon, which is shown at the bottom of this post.

In future posts I plan on giving some more detail into the development that went behind this tool as well as how to effectively use it, since there isn’t currently much in-game documentation. Though DSfM (or HSSIM as we like to call it internally) is technically in the “game” category, what it really is a research tool to help you understand and maximize your enjoyment of Blizzard’s wonderful Hearthstone game, which is also free on the app store. If you haven’t tried out Hearthstone, please check out it out I’m sure you’ll quickly get addicted!

So feel free to try out our app and give feedback, since refining any software to reach greatness requires an active user community.

Here is a link to the app:




Welcome to Deck Simulator for Hearthstone’s page!

This site is for the iOS iPad application Deck Simulator for Hearthstone. Here we will give information about releases, the tool itself, and also take support requests.

The app has not been released yet but it will hopefully be on the app store in a few weeks or less, so please check back here again soon.


Disclaimer: Hearthstone is a registered trademark of Blizzard Entertainment. This website and the HSSim tool are in no way associated or endorsed by Blizzard Entertainment.