Yield Protocol is Live

Allan Niemerg
Yield Protocol
Published in
4 min readOct 19, 2020


The Yield App

We are proud to announce the beta launch of the Yield Protocol on the Ethereum mainnet.

As detailed in our whitepaper and announcement post, Yield Protocol brings fixed-term, fixed-rate lending and interest rate markets to decentralized finance. Yield Protocol v1 enables fixed-rate borrowing and lending of Dai, using a new core DeFi primitive, fyDai (short for “fixed yield Dai,” with “fy” pronounced as in “fire”).

The protocol is now live and fully functional on mainnet. You can get started by pooling Dai in the automated liquidity provider to support liquidity in the system and earn trading fees and interest. Users can use Yield to borrow Dai at fixed rates with ETH collateral, or lend Dai at fixed rates, in quarterly maturities through December 2021 (as well as a beta maturity expiring in two weeks, at the end of October 2020).

We plan to move out of beta in early November, once the October 2020 maturity has successfully matured. Additionally, since interest rates are set entirely by the market, borrowing and lending rates may be unstable until there is sufficient liquidity in the pools.

The smart contracts have been audited and tested, but this remains a beta test, and you should treat it as such. There is always risk with depositing into new systems, and we urge you to use extreme caution as you start to experiment with this new primitive. We expect that there will be unexpected emergent behavior as a result of people using Yield in novel ways, and we do not have the ability to control or prevent users from using the smart contracts as they please, so you should keep that in mind as you interact with Yield. In the event of any issues or bugs, we do not have an administrative key or ability to change the smart contract, so any funds placed in Yield, especially during this beta, may be subject to total loss. Do not experiment with the Yield beta if you are not presently prepared to accept this risk.


Below is a quick walk through on everything we are releasing today.

The Yield App

To Yield App provides easy access to the Yield Protocol. You can use the app to borrow and lend Dai, as well as provide liquidity in the Yield liquidity pools. Visit app.yield.is to get started. This is simply a user interface, however, and all smart contracts can be accessed on chain. Over the next few weeks, we hope to see different dashboards and tooling emerge for Yield from other interested developers.

Yield Protocol Discord

Come talk with us about Yield at our Discord server. While we are the original developers for Yield, this is ultimately intended to be a community led primitive, and we want to help as many other developers and platforms learn and use Yield as we can. Get started here.


Yield Protocol v1 was audited by Trail of Bits. You can read their audit report here.


Documentation for the Yield Protocol and the Yield App may found at: https://docs.yield.is


The Yield Protocol includes maturities that expire at the end of the day on the following dates:

  • October 31, 2020
  • December 31, 2020
  • March 31, 2021
  • June 30, 2021
  • September 30, 2021
  • December 31, 2021

fyDai for these maturities were created by our team as the initial developers of Yield. Anyone can independently develop and deploy different maturities using the source code of the Yield Protocol.

Open Source Code

The Yield Protocol is open source and released under a GPL v3 license. You can view our code on Github.

Liquidator for undercollateralized positions

Similar to Compound and Maker, Yield requires off-chain participants to monitor undercollateralized positions and liquidate them. We are releasing a liquidator written in Rust, which uses the Uniswap V2 ETH-DAI pair’s liquidity via flashloans. You can view its code at: https://github.com/yieldprotocol/yield-liquidator/

Prefix change

When we released our Yield Protocol whitepaper, we called the tokens representing borrowing and lending “yTokens,” after the name of the protocol. Since then, the YFI community has adopted the name yTokens for tokens with completely different purposes. Out of respect for their usage and to avoid any user confusion, we renamed our tokens to “fyTokens.”

Bug Bounty

Yield is offering bounties for bugs disclosed to us at security@yield.is. The bounty reward is up to $25,000, depending on severity. Please include full details of the vulnerability and steps/code to reproduce. We ask that you permit us time to review and remediate any findings before public disclosure.

If our mission at Yield Protocol sounds interesting to you, we’re hiring! Applicants for solidity engineering and front-end development may be sent to contact@yield.is.