Anubis moved its anti-scraper proof of work to WebAssembly.

v1.28.0-pre1 replaces JavaScript proof-of-work with Rust compiled to WASM using SIMD acceleration where the browser supports it, and the difficulty scale changes from leading nibbles to leading bits (GitHub). Clients disabling WebAssembly fall back to pure JS via wasm2js, which is slower because those clients typically disable the JIT too, and the progress bar doesn't update during that fallback. The write-up took 293 points on Hacker News.