Real-time decision support and analytics for the evolving Bitcoin ecosystem

Optimize Your Fees API Reference

Fees are important.

As block space becomes more competitive, the importance of optimizing transaction fees grows. The emerging fee market, which in the winter of 2017/2018 saw Bitcoin fees briefly rise above $50/tx, proves the need for an improved, enterprise-grade fee estimation service.

Many estimators ignore the mempool and focus only on historical transaction data. Others focus exclusively on the current mempool, ignoring history.

NGB Fees employs machine learning algorithms to build a predictive model from a large sample of historical data. We then apply this model to our production mempool image. This creates a fee estimation model that is tunable, reactive, and accurate. Our goal is to increase your confidence and remove uncertainty when making on-chain transactions. Save on fees, improve your confirmation time, and avoid stuck transactions.

Once a predetermined number of coins have entered circulation, the incentive can transition entirely to transaction fees and be completely inflation free.

Satoshi Nakamoto, Bitcoin: A Peer-to-Peer Electronic Cash System

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NGB Fees is...


Evaluate tradeoffs between confirmation time, transaction cost, and confidence level to select fee rates that best suit your business needs.


Constant data updates mean our API never reflects a stale mempool state, allowing you to adjust quickly to sudden changes such as a spike in network activity or several quickly mined blocks.


Rest easy knowing that whatever your requirements, NGB Fees will provide the lowest fee estimates while still meeting your goals.

API Reference

Fee Rate Table


  • Returns a JSON object with all fee rates by block target and confidence
  • Fee rates are in Satoshis/Byte


Specific Fee Rate


  • Select block target: 1, 2, 3, or 6 (~10, ~20, ~30, ~60 minutes, respectively)
  • Select confidence: Between 90-99
  • Returns a single fee rate
  • Fee rates are in Satoshis/Byte


Coming Soon

  • Transaction Evaluation/Monitoring
  • RBF (Replace-By-Fee) Support
  • CPFP (Child-Pays-For-Parent) Support

About Us

Next Gen Bitcoin uses advanced analytics to empower businesses to make better decisions when interacting with the Bitcoin network. Our current focus is on improving fee estimation for businesses with high transaction volume. We are working toward delivering even more sophisticated algorithms to support Replace by Fee (RBF) and Child Pays for Parent (CPFP) decisions.

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