The Flipper Zero is marketed towards hackers but on the device itself there is no way to write code. Most programming languages use syntax and such that would make it very hard to someone to write code with the Flipper’s few buttons. There is one language though called Brainfuck which could be used and one could code it on the Flipper itself.
Some information on Brainfuck…
Notable for its extreme minimalism, the language consists of only eight simple commands, a data pointer and an instruction pointer. While it is fully Turing complete, it is not intended for practical use, but to challenge and amuse programmers. Brainfuck requires one to break commands into microscopic steps.
I think a compiler for this language should be created as well as an editor that one can use on their Flipper.