Oracles
Each market has its own oracle instance. The oracle provides ETH pricing in the market’s fiat currency to the CDP contract.
Dual Feed Design
The oracle checks two price feeds in order and returns the first valid result:
- Chainlink (primary) for ETH/USD
- RedStone (fallback) for ETH/USD
If both feeds are unavailable or stale, the oracle falls back to the last known good price stored in the contract.
Non-USD Markets
For currencies other than USD, the oracle includes a translator feed. This is a Chainlink aggregator for the target currency’s exchange rate against USD.
For enCHF, the oracle takes the ETH/USD price and translates it through a Chainlink CHF/USD feed to derive the ETH/CHF price.
If the translator feed goes stale, both base prices are rejected since they cannot be translated. This means the enCHF market can pause independently if the CHF/USD feed is unavailable, while the enUSD market continues operating normally.
Staleness Thresholds
Each feed has its own staleness threshold. A price older than its threshold is rejected and the oracle moves to the next source.
| Feed | Threshold |
|---|---|
| Chainlink ETH/USD | 6 hours |
| RedStone ETH/USD | 24 hours |
| Translator (CHF/USD) | 24 hours |
Feed Addresses (Ethereum Mainnet)
| Feed | Provider | Address |
|---|---|---|
| ETH/USD (primary) | Chainlink | 0x5f4eC3Df9cbd43714FE2740f5E3616155c5b8419 |
| ETH/USD (fallback) | RedStone | 0x67F6838e58859d612E4ddF04dA396d6DABB66Dc4 |
| CHF/USD (translator) | Chainlink | 0x449d117117838fFA61263B61dA6301AA2a88B13A |
The ETH/USD feeds are shared by both the enUSD and enCHF oracles. The CHF/USD translator is only used by the enCHF oracle. The enUSD oracle has no translator — it reads ETH/USD directly.
The CDP enforces its own 24-hour maximum age independently. Even if the oracle returns a cached price, the CDP will reject it if the timestamp is too old.
Validation
Every price read goes through validation before being accepted:
- Price must be greater than zero
- Timestamp must not be zero or in the future
- Chainlink specific: roundId must be valid, answeredInRound must match
- All external calls are wrapped in try/catch so a reverting feed is treated as unavailable, not as an error
No Deviation Check
The oracle does not compare prices between Chainlink and RedStone. In volatile markets, one feed may update faster than the other. A deviation check could reject a valid price because the other feed hasn’t caught up yet. In an immutable system, a rejected oracle means frozen liquidations and frozen withdrawals. Liveness is prioritized.
Price Format
All prices are normalized to 18 decimals regardless of the source feed’s native precision. The price represents fiat per ETH (e.g. $2,500/ETH = 2500e18).