Constraint programming is used in a variety of fields ranging from simple puzzle solving to big instances in industry. Currently Julia does not have a package for constraint programming and JuMP itself is in the beginning of implementing constraints and variable sets to support constraint solvers in the future. ConstraintSolver.jl is a new Julia package to tackle the problem of solving constraint programming problems purely in Julia. This has advantages for prototyping new ideas which is harder to do in low level languages like C or C++. Additionally the solver will be able to solve problems with different types than just integers and floating point numbers i.e. an integration with Unitful.jl will be possible. Another advantage of a solver purely written in Julia is to easily use automatic differentiation.