Hackattic
Fetch a problem from an API, solve it with code, post the answer
Hackattic is a set of practical programming challenges solved over HTTP. For each one, your program fetches a problem as JSON from an API, solves it, and posts the answer back. Tasks include unpacking binary data, making odd SSL certificates, reading a Redis dump file, brute forcing a ZIP file, serving DNS and hosting git.
Free · API · Advanced
About Hackattic
These are not classic algorithm puzzles. They test skills you use at real jobs, like parsing file formats and working with network protocols. It suits experienced developers who want hard, practical problems.
There are about 18 challenges, each worth a set number of points. You can browse them without an account, but requests use a personal access token. You can sign up with GitHub.
On Breakpoint since 23 Oct 2026.