Exactly Protocol
  • Getting started
    • 🔔Welcome
    • ➡️Introduction
    • ❔FAQ
    • 🔗Quick Links
  • Governance
    • 🏛️Exactly Protocol Governance
      • ✍️Proposals and Voting
      • ⚡Snapshot
      • 📄Exactly Improvement Proposal (EXAIP) Template
    • ⚫Exactly Protocol (EXA)
      • 📊EXA Tokenomics
      • ⚪EscrowedEXA (esEXA)
      • EXA Staking Program (stEXA)
  • EXA APP
    • The Exa App
    • How the Exa App works
    • The Exa App Webauthn Owner Plugin
    • Exa Plugin
    • Exa App FAQs
  • Guides
    • ⚙️Protocol
      • Auditor
      • MarketETHRouter
      • Market
        • ERC-4626
      • PriceFeedWrapper
      • PriceFeedDouble
      • InterestRateModel
      • RewardsController
    • 🛰️Peripheral Contracts
      • 🌀DebtManager
      • ⚫EXA
      • ⚪esEXA
      • 🪂Airdrop
      • 👀Previewer (read-only)
      • 👓DebtPreviewer (read-only)
      • RatePreviewer (read-only)
    • ✨Features
      • Bad Debt Clearing
      • Dynamic Close Factor
      • Earnings Accumulator
      • Cross-Asset Leverager & Deleverager
      • Liquidity Reserve
      • Rewards Distribution Model
      • Rate Manipulation Prevention
      • Rollover
    • 💲Fixed Rate Operations
      • 📥Deposits
      • 📤Borrows
    • 🔢Parameters
    • 📈Interest Rates Curves
    • ♻️Liquidations
      • 🤖Exactly's Bot
    • ⛓️Smart Contract Addresses
    • 🌐The Graph
    • 🔮Chainlink Price Feeds
  • Security
    • 🔎Audits
    • 🔑Access Control
    • 🛡️Hypernative
    • 🧪Testing
    • 🧯Emergency Procedure
    • 🐛Bug Bounty Program
  • Resources
    • 📃White Paper
    • 🔣Math Paper v1
    • 🔣Math Paper v2
    • 🤝Partnerships
    • 📺Presentations
    • 📣Brand Assets
  • Legal
    • ⚖️Terms and Conditions of Use
    • 🔏Privacy Policy
    • 🍪Cookies Policy
Powered by GitBook
On this page
  • OP Mainnet
  • Ethereum Mainnet
  • Chainlink
  • Uniswap TWAPs
  • Price Denominations
  • Deprecated Chainlink interface

Was this helpful?

  1. Guides

Chainlink Price Feeds

PreviousThe GraphNextAudits

Last updated 1 year ago

Was this helpful?

Exactly Protocol uses to get reliable, up-to-date, and secure asset prices to calculate users' lending power and .

OP Mainnet

Asset
Price Feed

esEXA

EXA

OP

USDC

WBTC

WETH

wstETH

Ethereum Mainnet

Asset
Price Feed

DAI

ETH

USDC

WBTC

wstETH

Chainlink

Uniswap TWAPs

After Ethereum's upgrade from proof of work to proof of stake, block proposers are chosen deterministically before they validate blocks. This feature creates new challenges for decentralized price oracles, like those provided by Uniswap V3, because they open up more significant potential for inter-block price manipulation, as detailed below.

Block proposers are alerted when they are selected to propose a block. This gives them a unique opportunity to carry out oracle manipulation attacks. If they are chosen to propose block n, they can attempt to manipulate the spot price on block n-1, knowing that they will be free to arbitrage their price manipulation on the next block (and censor any other attempts at arbitrage).

It is hard to estimate how many block proposers will view oracle manipulation attacks as a legitimate way to increase their income. It seems likely many will not take the risk of carrying out these kinds of attacks. However, as long as the number is non-zero, it is clear there is some reduced cost for carrying out these possible attacks.

Price Denominations

All asset prices, including stablecoins, are accurately reflected by querying them from live, and regularly updated price feeds. This approach avoids hardcoded values, providing users with reliable and up-to-date pricing information.

On Optimism, prices are currently retrieved and used in USD denomination due to lower availability in price feeds offered by Chainlink.

It's important to notice that this difference is only spotted at a smart contract level and does not imply any variation in the result of the health factor calculation. The web app shows prices in USD denominations for a better understanding from a user's perspective.

Deprecated Chainlink interface

It is worth noting that another difference with checking liveness is that transactions would revert in case of outdated updateTimes but as a downfall this may potentially hinder liquidations. We have carefully weighed the trade-offs and decided to assume the associated risks while focusing on reducing gas costs for our users.

We remain committed to the security and reliability of our protocol and will continue to monitor and evaluate any third-party integrations.

Chainlink is the most used data provider in the industry. It provides secure pricing feeds and is the DeFi standard Oracle network with . No liveness checks are performed while retrieving Oracle data. Chainlink offers robust and historically stable price feeds, even more on Mainnet for high-liquid assets such as WBTC, ETH, and DAI. Also, avoiding this check can lower the gas consumption of the involved transactions. The following contracts depend directly on Chainlink's price feed: , , and .

Other sources, such as , have been considered but finally discarded.

On Mainnet, the obtains and uses prices to calculate accounts' collateral and debt values in ETH denomination. In this way, an extra call (ETH-USD) is saved, which translates to a reduction in gas consumption for liquidity checks.

Exactly's smart contracts are fetching asset prices through a .

In a , we already acknowledged this decision in the spirit of transparency. We assured our users that we have assessed and taken appropriate measures to mitigate the associated risks.

Our choice to continue using this deprecated interface is based on several factors. We have implemented a low minimum timelock delay (1 day) and an upgradable , which enable us to respond swiftly if prices are not being updated accurately.

We have confidence in the robustness and historical stability of Chainlink's price feeds, particularly for highly liquid assets, the only ones enabled as .

🔮
Chainlink's data feeds
health factor
over six trillion transactions value enabled
Auditor
Price Feed Wrapper
Price Feed Double
Uniswap's TWAPs
Auditor
deprecated interface provided by Chainlink
previous audit by Coinspect (EXA-36)
Auditor
Markets
PriceFeedesEXA
PriceFeedEXA
PriceFeedOP
PriceFeedUSDC
PriceFeedWBTC
PriceFeedWETH
PriceFeedwstETH
PriceFeedDAI
PriceFeedETH
PriceFeedUSDC
PriceFeedWBTC
PriceFeedwstETH