Introducing Unique Identity (UID), the First NFT for Identity.

Mike Sall
Warbler Labs
Published in
3 min readNov 2, 2021


View the whole animation on OpenSea:

The Goldfinch community is excited to announce Unique Identity (UID), the first NFT for identity. Since the Goldfinch protocol opened in July, 33K people have already completed KYC (“know your customer”) through the protocol. While we originally built this for Goldfinch’s “trust through consensus” mechanism (described in the whitepaper), we realized it could benefit the entire ecosystem. So now, this growing community is eligible to mint their UID and make it available to the rest of the DeFI space.

Having an on-chain representation of personhood achieves two major unlocks:

  1. It opens DeFi to an entirely new set of real-world participants, notably companies and financial institutions.
  2. It greatly expands the design space for new features and mechanisms on DeFi protocols.

Many companies today don’t interact with DeFi due to KYC and counterparty concerns. But UID solves these issues for them. We know this first hand because many companies are already borrowing through Goldfinch, and they wouldn’t have without the KYC verifications. As companies grow comfortable with DeFi, they could drive an incredible amount of new volume.

Perhaps even more exciting is the wider design space this opens up for DeFi. Because UID provides strong sybil resistance, it can be used to implement more sophisticated governance (eg. quadratic voting), referral programs, fairer airdrops, reputation, and more.

To facilitate this, UID is completely interoperable with the rest of DeFi. It is a standard ERC-1155 contract, so any protocol can get the benefits without having to build their own KYC flow or handle any data themselves. If you’re a builder, check out the docs here to learn how to integrate it.

It’s also important to emphasize that we take privacy very seriously. No personally identifiable data is stored on-chain. We have partnered with Persona to manage the KYC process and data. They offer industry-leading privacy and security practices that are trusted by many of the largest technology companies.

How it works

When a user completes their KYC process, Persona checks that they have a valid identity and are not a duplicate of other ones. Once verified by Persona, the user is eligible to get their UID. They do this by submitting an Ethereum transaction that mints the UID, which is a non-transferrable NFT that is sent to their address. There is a 0.00083 ETH fee (about $3) in addition to gas, in order to cover the cost of Persona’s service.

Then, when the user participates in protocols like Goldfinch, these protocols can check that they have this UID, ensuring they are unique and KYC’ed.

Get your UID!

To get your UID, go to Just complete the KYC process and then you can mint your UID. You can see an example of how it looks on OpenSea here.

To start, UID will only be available to non-US individuals, but we are working on opening up in the US soon as well.

About the artist

The amazing illustration for UID was created by Marcelo Meijome. You can see some of his other NFT works on Foundation.



Mike Sall
Warbler Labs

Cofounder at @Goldfinch_fi. Previously Head of Product Analytics at @Coinbase, Head of Data Science at @Medium.