Property valuations in the USDR treasury are managed by third parties and decentralized oracles. Updated price oracles allow for collateralization ratios and minting on gains to be in “real time" while enhancing the decentralization of USDR and the Tangible ecosystem.
The following parties play a critical role in the maintenance and timely updates to Tangible’s real estate values:
Independent property valuations in the UK are provided by Hometrack.com, the largest Real Estate data provider in the UK, who are responsible for valuations on the majority of UK mortgages.
Hometrack’s valuations are updated on the third Thursday of every month and are delivered to the node through their API, which Tangible maintains a license on.
Develop and maintain the oracle and node which manage the inflow and outflow of pricing data.
This entire system uses the Chainlink node and oracle contracts making Chainlink integral to every part of the integration. Their custom infrastructure together with Chainlink automation (used to trigger the node to make a request for data) are a central piece of the architecture.
In circumstances where properties haven’t yet been indexed by the UK land registry and added to Hometrack, Tangible maintains the API which provides Royal Institution of Chartered Surveyors (RICS) accredited valuations to the node. These “paper” valuations are always available in the dropbox folder for the specific property.
The following are the key technical pieces of the system along with their function.
The node sits central to the source data (via APIs), the oracle and Tangible (marketplace, USDR treasury, UI). The node is the project manager of the operation, pulling in key information from the relevant sources and sending new information out when necessary. All data runs through the node.
The oracle is a smart contract with the most recent on-chain valuation data. The information it stores includes fingerprint data (home ID), timestamp on the last update/call to pricing, currency designator, location and the current home price (including one time costs like tokenization and other fees). The oracle manages the updates of its own data, pulling from the node.
An oracle wrapper was built which allows the oracle to integrate with our existing infrastructure.
APIs are the source of external data. In this case, Tangible licenses the Hometrack API which provides updated valuation data to the oracle (via the node) monthly. Tangible manages a secondary API with the remaining property valuations from independent third parties, homes not yet indexed by Hometrack.