Concord

Inspiration

Apps like Duolingo keep us learning every day with streaks, so we figured: why not use the same trick to get people to hang out? We've all run into someone, said "we should hang out," and then never actually did it.

What it does

Concord lets you "bump" phones with a friend when you see them in person, and each bump grows your streak with them. It also connects to your Muse agent, which helps your group chat find a time that works for everyone. Photos from your hangouts show up as memories, tagged with who was there.

How we built it

The bump verification runs on Solana, because we wanted every hangout to be provable. When two phones bump, they both sign a proof that you were together. That works even with no signal, and the proof gets recorded on Solana once you're back online. The app is native iOS in Swift, and the Dynamic Island plays a flame animation when you bump. For Muse, we wrote a TypeScript server that lets your agent check your streaks, plan with your friends' agents, and find real places to go through SerpApi.

Challenges we ran into

The hardest part was getting two phones to reliably find each other and agree on a bump. None of the phone-to-phone features work in the simulator, so every test meant two iPhones in the same room.

Accomplishments that we're proud of

A bump still counts in a basement with zero bars, because the proof is saved on the phone and uploaded later. We also like that Muse can plan the hangout for you, while the streak only moves when you actually show up.

What we learned

The big one was building an MCP server so Muse could talk to Concord. We also learned how Apple's phone-to-phone APIs work and how to record something that happened in real life on a blockchain.

What's next for Concord

We want to get it on the App Store and add group bumps, so the whole friend group counts at once. Longer term, people shouldn't have to know there's crypto involved at all.