Daily Coding

Daily Coding publishes one programming challenge every day. Everyone gets the same challenge, and it stays up for 24 hours, the idea is borrowed from Advent of Code, but it runs all year instead of twelve days in December.

You write your solution in the browser and run it against the test cases in one of 11 languages: JavaScript, TypeScript, Python, PHP, Ruby, Java, Go, C++, C#, Rust and Swift. Code is executed in a sandbox on the server, and results usually come back in well under a second. Once you submit, you can read every other solution to the same challenge, which is often more interesting than the challenge itself.

Signing up is optional. Today's challenge can be solved without an account; an account adds streaks, a profile and a place in the ranking.

The project is free, non-commercial and open source under the MIT licence. There are no ads, no paid tier and no upsell. The challenge library currently holds 40 challenges and grows over time; the source code, including the sandbox setup, is public.