I’ve been working on a small side project recently, a WhatsApp-based expense split bot. The idea came from something simple: whenever we travel or go out for dinner, someone always ends up calculating everything manually, and it becomes awkward chasing people later.

UPI apps like PhonePe and Google Pay technically have split features, but most people I know just use them for payments. Hardly anyone opens the split section, and no one really wants to install another app just for dividing money in a small group.

So I tried building a WhatsApp-first flow instead. The user just sends “Hi”, shares contact cards of the people involved, enters the total amount, and the bot handles the rest , including sending consent requests and notifying the creator if someone accepts or declines.

It’s built using the Meta WhatsApp Cloud API with a Spring Boot backend, MySQL database, and deployed on AWS. Still very much in the MVP stage, payment link integration isn’t added yet, that’s something I’m planning for the next iteration.

I’ve attached a short demo video showing how it works.

The most interesting part for me was designing the consent flow and handling WhatsApp’s 24-hour messaging window rules cleanly without making the experience feel complicated.

Curious to hear how others here think about conversational SaaS products or building on top of messaging platforms. Would appreciate any thoughts.

Built a WhatsApp-based expense split bot as an MVP, would love thoughts