Links to various repositories including some less well known constraint solvers. This is mainly so that I can find them again. I don’t make any claims that the list is complete.

• Huub New LCG Solver.
• Pumkin a proof carrying lazy clause solver written in Rust.
• Munchkin a lazy caluse solver written in Rust for teaching purposes.
• Tempo a constraint solver in C++ by Emmanuel Hebrard for solving disjunctive scheduling problems.
• NuCS: A native Python solver that uses numpy for speed.
• The Glasgow Constraint Solver a proof logging constraint solver.
• MiniCP in C++ by Laurent Michel and his students. It is mainly used for research. It has a FlatZinc parser. It also includes Haddock a system for using MDDs for propagation.
• Not really a constraint solver, but CPMpy is a python library for modelling constraint problems that interfaces to various constraint solvers.
• Choco is a constraint solver written in Java.