It listens to public relays for NIP-57 zap receipts, verifies them, and totals activity hourly to show how bitcoin micropayments move across the network. The site offers a live feed of recent zaps, along with leaderboards for the most-zapped accounts, top zappers, and popular content. Visitors can explore activity across time periods, including the past hour, 24 hours, 7 days, 30 days, or all time, and filter content by notes, episodes, tracks, and streams.

Each feed entry displays details such as the sender, recipient, amount in sats, associated content, and any available comment or interaction type. Summary statistics include total sats zapped, zap counts, activity rates, and hourly peaks. By presenting this information in an accessible, continuously updated format, zap.

observer helps users follow tipping and engagement on Nostr. The site states that it is not affiliated with any wallet, relay, or client