What are some of the open source Chess engines under the MIT license?

The purpose of the search is to find a suitable strong engine to be used in our chess hardware/software product. Thanks.

  • Why do you need MIT Licensed engines? Just curious.
    – ferit
    Commented Dec 29, 2015 at 4:57
  • Some parts of the GNU license are vague. Like, it states that if I create something out of the code, I'll have to open source that as well, and doesn't mention the specifics. As far as I know, MIT license is better if someone plans to make a commercial product out of an open source project.
    – Arun J
    Commented Dec 29, 2015 at 5:06
  • 1
    In GPLv3, you can use it for commercial uses, in GPLv2, you are right, it has restrictions. Check if they are in GPLv3. Also, they often say GPLv2 or later, in that case, you can assume it's GPLv3.
    – ferit
    Commented Dec 29, 2015 at 5:10
  • 1
    You can use commercially, but you have to open the source it seems. Strong copyleft licenses don't let to close the source, but weak copyleft's like LGPL let. I recommend to read this: en.wikipedia.org/wiki/Copyleft
    – ferit
    Commented Dec 29, 2015 at 5:33
  • @Saibot Although you're technically correct, chess is different because most engines started by process (inter-process communication). Thus it's not essential to open up the source code even it's bundled with a GPL software. If you want to know more, start a new question.
    – SmallChess
    Commented Dec 29, 2015 at 8:09

3 Answers 3

  • Crafty
  • Arasan

I don't recommend Pulse or NG-Play in the other answer as they're no longer maintained. The three engines I cited are still very active.

  • Micromax is too weak, isn't it? AFAIK, the aim of the Micromax is to be tiny. I think OP wants a strong engine to build upon.
    – ferit
    Commented Dec 29, 2015 at 8:17
  • @Sailbot When did the OP stated he wanted a "strong" engine? He was just asking for an open source engine.
    – SmallChess
    Commented Dec 29, 2015 at 8:18
  • "I think", when someone wants an engine to modify and redistribute as a commercial product, wants a strong engine to build upon. Do you disagree?
    – ferit
    Commented Dec 29, 2015 at 8:20
  • @Saibot We don't know what he's doing and we shouldn't assume. It's fine to distribute a "weaker" engine. In fact, I've been selling MicroMax on the iOS quite easily. Search for "Chess Mini iOS" and you'll see.
    – SmallChess
    Commented Dec 29, 2015 at 8:21
  • Are you selling an engine, or selling a chess playing app running some engine which users don't care? I think these are different things. When you sell an engine, you need your engine to be very strong.
    – ferit
    Commented Dec 29, 2015 at 8:23

Some searching yielded:

  • NG-Play doesn't fit the MIT licence. The author has not put in a clear licence, but he writes (in the sources) that the whole thing has to stay open source. More in line with the GPL. From the source text: /* Author: George Georgopoulos (c) 2010-2014 */ /* You are free to copy/derive from this code */ /* as long as you mention this copyright */ /* and keep the new code open source */
    – Ras
    Commented Aug 28, 2016 at 9:50

Fairy-Max and micro-Max are not particularly strong, but they are in public domain and have been used in different devices.

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