[casta]

Happy to share! It's vanilla nodejs, no additional framework used (nothing like express.js or anything like that). The search stuff is just a bunch of custom in memory data structures, there is reverse index, plus a mapping of common misspellings, plus some prefix to likely words, plus some n-grams.

For the frontend is just plain js and html.

If you have a more specific question feel free to ask and I'm happy to answer.