project screenshot 1
project screenshot 2
project screenshot 3
project screenshot 4
project screenshot 5


HomoSapienSays is a service where only 'real people' share reviews of places they have 'actually visited'.


Created At

ETHGlobal Istanbul

Winner of


Worldcoin - Honorable Mentions

Project Description

HomoSapienSays is a service where only "real people" share reviews of places they have "actually visited". There are significant issues with existing online review systems, such as spam by bots/AIs, and reviews of places never actually visited. HomoSapienSays resolves these problems of existing online reviews by using World ID to verify that a user is a real person and by using Arx's NFC cards to prove that they have visited a specific place. Furthermore, by utilizing zero-knowledge proofs, the service maintains anonymity while limiting users to one review per location. Additionally, it does not hold any information that links users across multiple reviews.

How it's Made

HomoSapienSays uses Worldcoin's World ID to verify that a user is a real person. Additionally, by utilizing the Anonymous Actions feature of World ID, it limits users to one review per location and acquires a different nullifier for each review.

As a method to prove a visit to a specific location, the service utilizes Arx's HaLo chip (NFC). By using Arx's HaLo chip to sign the nullifier hash of World ID, it is proved that a real human has tapped the Arx's HaLo chip. For example, if a HaLo chip is placed inside a restaurant, one cannot tap the chip without being in the restaurant, thereby proving the visit to that specific place.

The Frontend/Backend was implemented using Next.js (Vercel). Also, since I participated as a solo this time, I prepared four AI assistants (co-founder, designer, frontend engineer, backend engineer) and developed the project in collaboration with AI assistants, from brainstorming ideas to implementing code and design.

background image mobile

Join the mailing list

Get the latest news and updates