Augur: Block’s Open Source Bitcoin Fee Estimation Library

Augur is a cutting-edge tool designed for generating real-time fee recommendations for Bitcoin transactions. This tool stands out because it bases its estimations on live mempool data rather than historical block data, aiming to provide more accurate and current fee suggestions. For those interested in integrating or experimenting with Augur, a reference implementation in Kotlin is available, showcasing how to use the library in projects. Additionally, Block provides a public API endpoint, updated every 30 seconds, for querying live fee estimates at https://pricing.bitcoin.block.xyz/fees, making it easier for developers and users to access real-time data.

The methodology behind Augur's fee estimation leverages a mempool-first approach, emphasizing the importance of current transaction volumes and the unpredictability of Bitcoin mining. By categorizing transactions in the mempool by their fee rate and monitoring the transaction inflow rates, Augur can predict confirmation times with varying degrees of confidence. This approach differs significantly from traditional models that rely heavily on past block data. The adoption of this model allows for dynamic adjustments to fee recommendations based on actual network conditions.

In assessing the performance of Augur against other major fee estimators, Block developed a custom benchmarking tool. This tool evaluates accuracy and cost-effectiveness by considering metrics such as miss rate, average overestimate, and total difference—a composite score reflecting both under and overestimation. Preliminary results demonstrate that Augur offers a balanced trade-off between reliability and cost, making it an attractive option compared to its competitors. Notably, during periods of normal-to-moderate mempool volatility, Augur delivered success rates comparable to other providers but at a significantly lower cost.

Looking ahead, Block plans to release an open-source version of their benchmarking tool. This move will empower the community to validate Augur's performance, compare it against other estimators, and potentially contribute improvements. The initiative underscores Block's commitment to transparency and collaboration in enhancing Bitcoin fee estimation methodologies. Developers and enthusiasts are encouraged to explore Augur and its reference implementation to understand better how it can benefit their applications and transactions on the Bitcoin network.