Brainfuck is an esoteric programming language created in 1993 with only eight commands. Building an interpreter for it is a great exercise in language implementation.
Despite its simplicity, Brainfuck is Turing complete. Implementing an interpreter covers tokenizing, parsing bracket-matched loops, managing a memory tape, and executing instructions. It’s an accessible entry point into building programming language tools.
Build your own Brainfuck Interpreter is available with a project breakdown on Coding Challenges.