Solver registrations for the 2024 MiniZinc Challenge are now open!

MiniZinc Challenge 2023

The Challenge

The aim of the challenge is to compare various constraint solving technology on the same problems sets. The focus is on finite domain propagation solvers. An auxiliary aim is to build up a library of interesting problem models, which can be used to compare solvers and solving technologies.

Challenge participants provide a FlatZinc or MiniZinc solver and global constraint definitions specialized for their solver. Each solver is run on 100 MiniZinc model instances. For FlatZinc solvers, we run the minizinc compiler on the MiniZinc model and instance using the provided global constraint definitions to create a FlatZinc file. The resultant FlatZinc file is then given as input to the provided FlatZinc solver. For MiniZinc solvers, the MiniZinc model and data are input to the provided solver. Points are awarded for solving problems, speed of solution, and goodness of solutions (for optimization problems).


  • 2023-09-14 Results have been amended to add the missing results for SCIP, and some models have been updated to correctly mark their symmetry breaking and redundant constraints.
  • 2023-08-30 Announcements of the results are here.
  • 2023-06-12 Call for solver registrations for the MiniZinc Challenge.
  • 2023-06-07 Problem submission deadline extended.
  • 2023-02-13 Official Call for Problems for the MiniZinc Challenge.


  • Registration opens: Now.
  • Problem submission deadline: Fri, 2 June 2023 Fri, 30 June 2023.
  • Solver submission begins: Mon, 12 June 2023.
  • Solver submission deadline: Fri, 28 July 2023.
  • Announcement of results at CP2023: 27 - 31 August 2023 (Toronto, Canada).


Entrants must register their intention to enter the contest before the final submission date.

To register, use the MiniZinc Challenge Submission System.


All entrants need to extend the MiniZinc Docker image (available at, tag latest) with their solver. Detailed information how to prepare the docker image are available here. The entrant will upload the extended image to Docker Hub and fill out a web form (provided after registration) providing the location of the image to the MiniZinc organisers.

Please carefully read the rules before submission.

Problem Submission

We strongly encourage all entrants to submit one or two MiniZinc models satisfying the contest requirements, together with instances for these models. All models will be considered for the MiniZinc Challenge, however we may need to make some modifications to them in order to ensure they are suitable for the challenge.

The sooner they are submitted the better, the deadline is Fri, 2 June 2023. The call for problem submission is available here. Please feel free to distribute it.


The rules for the MiniZinc Challenge 2023 are available here.
If we need to make changes to the rules, all registered entrants will be informed by email.


The judges will be responsible for selecting the tested instances, vetting the results, and ruling on any questions that arise during the competition.

  • Jimmy H.M. Lee. Chinese University of Hong Kong.
  • Barry O'Sullivan, University College Cork, Ireland.
  • Roland Yap, National University of Singapore.


This is the 15th time this challenge is being run, and there are many possibilities for comparing CP solvers. The rules try to make a sensible set of choices for the comparison. We welcome any comments or suggestions regarding the running of this challenge.

We can be contacted with the subject starting with [MZNC23] at:

mzn-challenge 'at'

MiniZinc forums

The MiniZinc forum is for beginners, users, and developers to discuss MiniZinc. If you would like to join then sign up for the MiniZinc forums.

The MiniZinc page includes a list of resources related to MiniZinc and FlatZinc.

The MiniZinc 2.7.6 Distribution includes a MiniZinc-to-FlatZinc converter and a large suite of MiniZinc examples and benchmarks.

The MiniZinc Challenge webpage, includes the results from each MiniZinc Challenge.