Wordle is pretty damn smart in many subtle ways
I actually think the OP and the comments are too focused on the programmer-related aspects of this. I'll add a few things.1. It's not trivial but it's not that hard if you have a decent vocabulary and some intuitive sense for word frequencies (and word pair frequencies) for different locations in a word. The answer list does not seem to include really hard words as naively picking all the words in the MW dictionary would be. It's a fun 10-15 minute puzzle.2. Five letter seems like something of a sweet spot.3. The answer word list does not appear to have a lot of plurals or common vowel endings for past tense, etc. Or obscure words.4. It lends itself to what I'll casual cheating, i.e. there are easy ways to get some hints without giving the answers away while focusing on a strategy.5. Basically, it's got good gameplay for a casual game. It would be easy to build something along similar lines that didn't have as fun gameplay for a casual gamer.