Show HN: Open a phone number in WhatsApp without saving contact

I made a simple HTML app that can help open a phone number in WhatsApp (web on desktop or app on mobile) without having to create a contact first.

Source code is available on GitHub. Enjoy and share it with your friends and family (they will thank you if they're using WhatsApp)!

I used ChatGPT 4 (even for the favicon) but couldn't say it was faster than writing it from scratch. It was a completely different kind of debugging and improvement process. What was really missing was a way for ChatGPT to automatically see the results of its code and do a few iterations to benefit from a feedback loop. Even just asking it to read its own reply and fix/improve it works wonders, but showing it screenshots is yet another step forward.