Volt is a stablecoin that aims to preserve purchasing power and mitigate the effects of inflation. It does this by tracking the Consumer Price Index (CPI).

Volt is part of the Fei Protocol family of projects, and shares a significant part of its codebase with Fei. We were approached to audit a component in Volt, the ScalingPriceOracle. The ScalingPriceOracle essentially is a chainlink client which brings CPI data on-chain through a chainlink oracle. We also reviewed the new global rate limited minter and non-custodial PSM, which were largely unchanged since our previous audit of Fei Core.

Zellic conducted an audit for Volt Protocol from March 21st to March 23rd, 2022 on the scoped contracts and discovered 4 findings. Fortunately, no critical issues were found. Of the 4 findings, all were informational in nature. We applaud Fei for their attention to detail and diligence in maintaining high code quality standards.

Volt is a stablecoin that is designed to maintain purchasing power, by tracking the Consumer Price Index (CPI). This data is fed on-chain through a chainlink oracle into the ScalingPriceOracle. This contract effectively implements a 1-month linear interpolation↗ to smoothly change value between one month and the next. During our review, we found that it correctly uses and implements the chainlink client in a fashion consistent with Chainlink's first-party documentation.

Much of the project's code base has already been audited previously. We were approached to audit the ScalingPriceOracle and its auxiliary code. We also reviewed the new global rate limited minter and non-custodial PSM, which were largely unchanged since our previous audit of Fei Core. We were instructed to leave the contracts and code outside the scope of this assessment.

Our general overview of the code is that it is very well-written and maintained. Within the assessment scope, the test suite reaches nearly 100% code coverage, and the project has adopted continuous integration. The documentation was clear, concise, and thorough. We hope Volt continues the commitment to high code quality that they have shown so far.