challenges.re
Read compiled code and work out what each function does
challenges.re is a collection of 87 reverse engineering exercises. Most give you a short piece of compiled code, often just a function, and ask you to work out what it does. The code covers x86, x64, ARM, ARM64 and MIPS, with some exercises for SSE and FPU code, .NET and Java.
Free · No login · Browser · Intermediate
About challenges.re
It trains reading assembly and turning it back into logic. Exercises are marked by level, so you can start simple. The author uses them for teaching, so no solutions are published.
The site is free and needs no account. You read the exercises in the browser, and you can email the author to check your answer.
On Breakpoint since 23 Oct 2026.