The challenge
What needed to change.
Property records are split across county offices and systems. Checking a property's history means chasing documents, and owners have nothing portable to show for it.
Scattered records
Deeds, assessments and tax data sit in different systems with no single source.
Slow to verify
Confirming who owns a property, and since when, means chasing paper across offices.
Private by nature
Deeds carry personal details, so publishing them openly isn't an option.
The engineering decision
Verifiable without being public.
A property passport needs a verifiable connection to the source record without publishing personal details. VTS separated public metadata and artwork from the deed itself: private documents stay in encrypted AWS storage, while a fingerprint is recorded on-chain. An authorized verifier with the source document can compare its fingerprint to the record. Public metadata and artwork use IPFS. This preserves privacy, while document access and full verification still depend on Keystone's controlled storage.
What VTS delivered
From decision to delivery.
Everything between a county record and a minted passport.
Passport contracts
ERC-721 passports on Base, one per property.
Verification pipeline
Each passport is checked against county data, the tax ID and the deed fingerprint.
Deed retrieval
A script pulls the latest deed for each property from the city records portal, checks the address and tax ID against it, and files it.
Batch minting
Tools to verify and mint properties in batches.
A registry for web2 users
Email sign-in through Privy and payment in dollars, with real on-chain records underneath.
The product flow
- 01
Source
Pull the county record for the property.
- 02
Verify
Retrieve the deed and check the address and tax ID.
- 03
Fingerprint
Hash the deed; the document stays in private storage.
- 04
Mint
Issue the property's passport on Base.
- 05
Check
Browse the public passport and its verification metadata.
Project facts
The first property passports
- 96+
- property passports minted Jul 2026
- Base
- live ERC-721 contract Live
- Philadelphia
- first market Live
Philadelphia rollout: 96+ property passports minted by July 2026.
Visit Keystone Digital RegistryWorking together
How we engaged.
VTS works as Keystone's solution architect: we design the platform, build it, and deliver it in phases alongside Keystone's team.
