Teender.
Teender is a portmanteau of 'teen' and 'Tinder.' A high-schooler logs in with Facebook, picks a crush from their Facebook contacts, and sends them an anonymous note. The crush sees the message but not the sender.
the story.
I was sixteen, building things every weekend. The problem statement was honest: a lot of social anxiety in high school is just the inability to send the first message. We thought: what if the first message was anonymous, and the person on the other end could only see who you were if you decided to reveal?
It used Facebook Login for identity (this was 2016 — Facebook was still where high-schoolers lived), and Firebase for the message thread. I designed the screens, wrote the iOS app, and ran the backend.
In hindsight, the product was a teenage version of a much-discussed adult one, and it had all the same problems — abuse vectors, no easy moderation, brittle anonymity. I wouldn't build it the same way today. But it was the first time I shipped something that other students at my school actually opened.