Hi. My name is Jeremy. Two of my favorite things in this world are basketball and programming, so I created Basketball GM, which later has become Zen GM.

Zen GM has single-player sports simulation games for Basketball and Baseball. Make trades, set rosters, draft players, and try to build the next dynasty, all from within your web browser.

To keep up-to-date on the latest news, check out our Basketball subreddit and our Baseball subreddit. Feedback is always welcome via either of those websites or by simply sending me an email.

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Gameplay Philosophy

I actually haven’t played a ton of other sports simulation games, but my favorite one is Baseball Mogul. I haven’t played it recently, but I played it lots ~10 years ago. My favorite thing about Baseball Mogul was that it was pretty simple. It didn’t force you to micromanage everything. Although there was a lot of power under the hood, you could also just jump in and start playing right away.

Based on this concept, my goal is for Zen GM to be a simple yet realistic simulation site. If simplicity and realism butt heads, simplicity will usually win.

MLB and the NBA are an influence of course, but Zen GM is not a MLB or an NBA simulator. There are myriad nuances of rules and regulations that would be incredibly tedious for players, so I avoid them.

Finally, I am strongly opposed to the “freemium” trend in gaming, recently popularized by FarmVille and Candy Crush and tons of other insanely profitable games. These games are not designed for maximal enjoyment. They’re fun enough to keep you playing, of course, but the real goal of them is to be annoying enough that they convince you to buy artificial power-ups within the game. This is a complete perversion of market incentives that normally should be perfectly aligned with the user’s best interest: the more fun the game is, the more people will play. Zen GM will always have that as its primary goal.


Zen GM games are 100% client-side HTML5/JavaScript apps. This means that all the simulation is done on your computer and all the data is stored on your computer. There is no server-side component. This magic is brought to you by IndexedDB. There are some disadvantages, such as less than ideal cross-browser support (fuck Apple) and the inability to easily copy saved games across devices. However, there are some huge advantages, most importantly that my server costs are basically $0, so you can play as much as you want for free.

I also want to thank all of the open source projects that Zen GM depends on (in alphabetical order):

If you want to know more about the history of Zen GM, read this.