tagtag
Leave AR stickers at real places, discover their notes, and collect the moments.
Demo
About
Tagtag is a Augmented Reality (AR) collecting game that doubles as a community building engine. Tagtag was heavily inspired by POAPs and Pokemon Go. The Proof of Attendance Protocol (POAP) transformed how event goers commemorate attending events by receiving on-chain NFTs. Nearly 7.6 million on-chain badges were minted and more than 46,210 unique event badges were created. On the other hand, Pokémon GO exploded into a global phenomenon that seamlessly blended the nostalgic world of Pokémon with cutting-edge augmented reality (AR) technology. By turning the real world into a massive, interactive game board, it shattered traditional gaming boundaries and compelled millions of people to step outside, explore their local neighbourhoods, and congregate in public spaces. Tagtag brings together the core ideas behind these apps: the joy of discovery and the meaning of collecting. We believe this combination can help people uncover new places, preserve memories as digital keepsakes, and create curated experiences worth sharing. [THE COMPLETED HACKATHON VERSION IS (0.2.0)] Testflight (iOS): https://testflight.apple.com/join/cUnAbdSY Figma: https://www.figma.com/design/8EuygwbCLAfBuSCuH1Yc5d/Tag-Tag?node-id=0-1&t=6h6X6aktQUN8mjbW-1
How it's made
Tagtag is built with Unity. We combined a playful sticker-book interface with location-based discovery. AR Foundation and ARKit detect surfaces, anchor stickers in the real world, and save the creator’s AR world map. When another person visits, their iPhone uses that map to recover the sticker’s placement, allowing them to find it, collect a copy, and unlock its accompanying note. Native MapKit displays nearby sticker locations and lets creators confirm a placement when GPS is approximate. Users can create stickers from their own images, take photos, or use optional Image Playground generation on supported devices. The interface uses paper textures, handwritten typography, and our mascot, Taggi, to make discovery feel like adding a small souvenir to a personal collection. The backend uses a Node.js API hosted on Google Cloud Run, with Firebase Authentication for identity, Firestore for application data, and private Cloud Storage for artwork and AR recovery files. It manages sticker publication, discovery, private-note access, and collection syncing. Collecting a sticker adds a copy to the finder’s book while leaving the original available for future visitors. Our Web3 layer extends these discoveries into transferable digital souvenirs. The implementation uses ERC-721 NFTs on Ethereum Sepolia. When enabled, a new collection queues a backend minting job, and Tagtag covers the minting gas. Minting runs asynchronously, so blockchain delays do not interrupt collecting or reading a note. Public NFT metadata contains generic Taggi artwork; private notes and location details stay off-chain. This gives a discovery a lasting, portable collectible that users can transfer to an external Ethereum wallet. The NFT integration currently targets the Sepolia testnet and remains behind a rollout flag pending configuration and verification. HACKY THINGS WE DID: ThirdWeb and Privy both required paid plans in order to work with external auth (i.e. Firebase). So instead of paying we decided to build our custom wallet in app. We used multiple methods of verifying if a user was actually at the location to collect the sticker such as GPS, ARKit, multiple photo angles.