Anonymous organization/team, no differentiating USP's, no privacy policy, no terms of use, no idea how/if this will be monetized (are we the product?). Also no source code, no decentralized social networking. Imho you should definitely bring more clarity in some of these areas.

if I had to nitpick, the "Slapped successfully" toast notification does not match the application's design scheme, imo.

Good idea, but "Privacy policy" - The page you are looking for does not exist.

Given how it will be used it could be a minefield.

congrats on building and shipping something, and thank you for sharing it here. i like the minimalism of your landing and signup pages. however there are some significant concerns to address:

why would anyone want to use this? what value does it provide? what is the experience like for the people who receive a Slap?

good luck don't give up.

imo, you should have went down a more fun/humorous route of slapping your friends