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Ampleforth Oracle Usage — An Amplified Look


Tellor is pleased to be working with Ampleforth to provide price data into its smart contracts. For those that don’t know how Tellor works, we’re a decentralized oracle that uses a network of staked data reporters who compete to fetch off-chain data and place it on-chain.

Ampleforth is now using Tellor to bring on two values: the AMPL/USD value and the US Personal Consumption Expenditures (a key measure of inflation).

AMPL 101

Ampleforth is the developer of AMPL, the first rebasing currency and a key DeFi building block. The AMPL protocol adjusts total supply daily based on market conditions. The AMPL protocol is based on its own unique primitives that make it uniquely poised to denominate stable contracts. Unlike stablecoins, AMPL does not rely on traditional banks or lenders of last resort. Each day, AMPL’s unique, rules-based protocol translates price volatility into supply volatility in a fully transparent manner. To put its rebasing model in perspective, consider this example: if AMPL is trading over a dollar, more AMPL is minted. If AMPL is trading under a dollar, AMPL is removed from circulation. Since price * supply = value (or Mkt cap for coins), if more people want to buy, the price will go up. In order to keep the price at a consistent level of denomination, the system automatically increases or decreases supply so that the equation holds. Ampleforth calls this process “rebasing.”

Why they need oracles

In order for AMPL to do its daily “rebase,” it requires a price of AMPL/USD on-chain so that the protocol knows how to adjust the supply. It doesn’t peg directly to the dollar, but rather an inflation-adjusted dollar. Using the US Personal Consumption Expenditures Price Index, it can track the value of the US dollar versus costs. This means that AMPL will still hold a stable value versus goods and services, even if the US dollar collapses in value. There is no reliance on traditional banks or lenders of last resort to guarantee liquidity.


The supply change is referred to as supply rebase and is applied daily at 2 AM UTC. The price used to compute the deviation from the market price is the volume weighted average of AMPL trades over the 24 hours of the previous day from midnight to midnight UTC across all markets/exchanges and pairs.

Tellor becomes the third oracle to power AMPL price feeds, joining Chainlink and Ampleforth itself. The median (or average, if there are only two) will determine the daily rebase to ensure the most accurate outcome each day.


Overall, Tellor is thrilled to be working with such a great team and project. Ampleforth is a pioneer in token economics and its team’s passion and drive toward decentralization is obvious. AMPL has established a robust system and uses most of the best practices for oracle users on Ethereum. The next steps taken to further decentralize the protocol and create more robust price feed will keep AMPL as one of the most cutting edge projects around.




Tellor is a transparent and permissionless oracle protocol for your smart contract to easily get any data whenever it needs it.

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