Human Wall
A guestbook where every verified human can leave exactly one message.
About
Human Wall is a simple, anonymous guestbook powered by World ID. Every verified human can publish exactly one short message, while bots and duplicate users are prevented from posting repeatedly. It demonstrates how proof of personhood can make online public spaces more authentic without requiring usernames, passwords, or personal information. Visitors can read messages from other verified humans, write their own message, and verify their uniqueness before publishing it to the wall.
How it's made
Human Wall is built with Next.js, React, TypeScript, and World ID IDKit. The frontend lets a visitor write a message and launch the World ID verification flow. The proof is sent to a Next.js API route, which verifies it through the World ID Cloud Verification API. After successful verification, the message and its anonymous nullifier hash are stored by the server. The nullifier is used only to prevent the same human from posting twice and does not reveal their identity. Messages are displayed in a responsive guestbook-style interface.