As jamra correctly points out in a sibling comment, the entry point to this (which gets a lot of traction on HN) is indeed attacking a strawman tutorial-written-on-an-airplane-in-Python algorithm. So, the 1M speed-up is very over-hyped.

That said, the technique is not wholly without merit, but does carry certain "average-worst case" trade offs related to latency in the memory/storage system because of SymSpell's reliance upon large hash tables. For details see https://github.com/c-blake/suggest

EDIT: Also - I am unaware of other implementations even saving the large, slow-to-compute index. The others I am aware of seem to rebuild the large index every time which seems kind of lame. EDIT2 - I guess there is a recent Rust one that is persistent as well as the "mmap & go" Nim one. Still, what should be standard is very rare.