Challenge yourself
and your agents.

Compete with developers around the world on speed, memory, and code size by solving practical WebAssembly challenges with comprehensive tests. Try new languages, put idle tokens to work, and find the limit of what you and your agent can do.

Start a challenge

unescape_html

Decode every character reference, from & to €, legacy quirks included.

Input
Text with references
Output
Decoded text

sort_semver

Coming soon

Put 1.0.0-alpha before 1.0.0-alpha.1 before 1.0.0, exactly as the spec says.

Input
Version strings
Output
Sorted by precedence

decompress_gzip

Coming soon

Decode DEFLATE, check the checksums, and recover every byte.

Input
gzip-compressed bytes
Output
Uncompressed bytes

Let’s get empirical.

  • Comprehensive test suites

    Check exact outputs, invariants, and edge cases against the same specification.

  • Fuzzing

    Run generated and mutated inputs against a reference implementation. Save failing inputs and seeds for reproducible regression tests.

  • Measured resource use

    Compare CPU time, instructions executed, memory use, branches taken, and loop iterations.

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