[RFC] Change sUSD pricing Oracle to Chainlink

Title: RFC for sUSD oracle moving to Chainlink

Authors: SNX Ambassadors

Related Discussions: N/A

Submission Date: 14th / Nov / 2022

Simple Summary

This proposal calls for changing the sUSD price oracle to Chainlink. It is submitted by Millie, a member of the Synthetix Ambassadors.


Currently, the sUSD price oracle is not useful because there is no sUSD-WETH Uni-V3 pairing. sUSD thus cannot be used on Euler. We would like to change that and bring sUSD to Euler. There is significant on-chain liquidity for sUSD, but it is fractured across several different liquidity pools.

sUSD-WETH has been supported on Chainlink for some time This oracle can be found here. Users of this oracle include Kyber, 1inch and Aave.


After some discussions with Euler community members, we’d like to strengthen the connection between Synthetix (as ambassadors for the protocol) and Euler. To us, enabling an sUSD market would bring great utility to an already productive asset.

In upgrading the sUSD oracle to chainlink, it will allow for us to bring sUSD without allocating scarce assets on a WETH pairing, something that does not really make sense for sUSD when a Chainlink feed exists.

While Euler enjoys permissionless listings, Chainlink would put sUSD at the top tier of oracle security in one swoop.

Specification & Implementation:

If passed, the sUSD market’s price oracle should be updated to use the Chainlink sUSD / WETH oracle see here:sUSD / WETH | Chainlink 1.

This oracle alternative was made possible by the recently passed eIP 14 and the implementation is similar to that called for in eIP 16 1.


  • Yes – the sUSD market should have its oracle changed to use the Chainlink sUSD / WETH oracle.
  • No – the sUSD market should find an alternative oracle.

Hey guys, I’m Matt from the Synthetix Ambassadors; just chiming in here to say that I support this proposal and can’t wait to see the great partnership that will develop between Euler and Synthetix.

Excited to see you guys come to Optimism, and support a wide range of synths and ecosystem partner tokens.


Hey guys, I’m MasterMojo from the Synthetix Ambassadors! I am also jumping in here to say that I support this proposal !

If you have any questions don’t hesitate to ask!


I have spent some time speaking about this issue with the SNX ambassadors and am very much in favour of this proposal. Activity in sUSD means growth in TVL terms for the protocol and an ever growing reserve.

Putting the asset onto chainlink will secure it and this is in my eyes a pre-requisite step for making it a collateral asset on the protocol. I look forward to hearing the thoughts from the rest of the DAO!


Switch to the Chainlink oracle has proven its value. So I would support this proposal!


Seems like a no-brainer to me.

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Also completely support this change. I would only add more assets to the upgrade list. Should also include CRV, BAL, BUSD, GUSD updates to Chainlink. Any others?

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that’s a good suggestion and I would be open to including those in the eIP if other delegates are in agreement on the idea

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This is a good idea. It’s tiresome constantly requesting changes. Let’s update all these assets!

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Nice idea! Additionally, I would make an announcement in Discord for the people, who are not active on the Forum, to be able to suggest another assets to be included in the final list.

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@Millie @euler_mab Have you considered using this function in the Uniswap v3 Oracle Library? It allows a price of any asset to be “chained” through other pairs so one can return a price for an asset pair where there is no actual initialized pair.

Not saying I’m against the proposal, but wanted to surface this incase it wasn’t already considered.

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hmm, I don’t think that we’ve ever discussed that. at a glance it might be harder to assess security of such an oracle considering multiple liquidity pools involved. anyways, worth looking into

As @euler_mab mentioned, it might be good to update to Chainlink all the other assets that have Chainlink price feed available. Here’s a list of such assets that have been activated on Euler since eIP 22:

  • RLC
  • XCN
  • ALCX
  • BAL
  • sUSD
  • GUSD
  • CRV
  • BUSD

Also, we might consider bringing back Chainlink for LRC. Its price feed was supposed to be deprecated at the time of writing eIP 22, but in the end only LRC/USD price feed was deprecated and LRC/ETH is still alive.


I do not see any reason why not. Fully support the amendment to the proposal.

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Okay it looks like there’s some good feedback here, I think this is ready to move to an eIP with the mentioned amendments.

It usually takes around 7 days to move from RFC to eIP proposal.

okay, no problem, 7 days it is!

hello again,

as we’re speaking about oracles here. there’s actually one more change that we can bundle together with what was proposed in this RFC so far.

at the moment, the oracle used for WBTC is BTC/ETH Chainlink price feed. at the time of implementation, it felt like a safe approach and done not only by us, but also by other protocols like Aave. however, such a solution does not protect the protocol in case of a black swan event like WBTC/BTC price drop which, even though highly unlikely, might be caused due to numerous reasons.

hence, I propose that we switch the oracle for WBTC to Chainlink-compatible oracle, a simple contract which does the following:

should WBTC/BTC price depeg, such an approach will protect the protocol from bad debt.

the pull request with contract implementation and appropriate tests can be viewed here. the contract follows the same pattern as other Chainlink-compatible oracles already in use that were created for assets that to not have underlying/ETH Chainlink price feeds available, but do have underlying/USD price feeds (i.e. MATIC or ENS)


I have no issue including this, but I do feel like that would be bundling too much into one eIP. It might be preferable to submit a standalone eIP for this upgrade.

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I have incorporated the feedback from @kasp as well as @euler_mab and have created an eIP reflecting those suggestions.

The proposal can be found here: eIP 30: Upgrading to ChainLink Oracles for several Markets