When you generate a checkout for a product or service with OpenNode, your customer may accidentally not enter enough Bitcoin to complete the checkout, resulting in an underpayment. This often occurs when the payer forgets to include a few extra sats to cover the network fees for an on-chain Bitcoin transaction.

In the result of an underpayment, the payer will recieve an email prompting them to either complete the payment or ask for a refund. Learn about how underpayments are returned to payers here.

Best practices & how to avoid underpayments

Set up an underpaid threshold

OpenNode offers an underpaid threshold feature that allows you to set a limit on what you are willing or not willing to accept for an underpaid checkout. Learn more about our underpaid threshold feature here.

Encourage payers to use a proper Bitcoin/Lightning mobile wallet rather than paying from an exchange

Mobile wallets are purpose-built to manage network fee payments; exchanges are not. Because of this, it is best practice to instruct payers to use a Bitcoin/Lightning wallet application to complete payments by either scanning the QR code or copying/pasting the BTC address. Please find some wallet recommendations here:

Blue wallet - A custodial wallet with On-chain and Lightning payment capability. Users also have the ability to purchase bitcoin directly on the wallet through P2P exchange HodlHodl. (Google Play/App Store)

Wallet Of Satoshi - A custodial wallet that supports Lightning payments. (Available Google Play/App Store)

Breez Wallet - An open-source non-custodial wallet with easy Lightning network channel set-up. (Google Play/App Store)


Suggest exchange users add a small fee buffer (0.0002 BTC) to payments to improve completion.

The reason exchange-using-payers have higher rates of failure is that the payer does not cover the network fee required to complete the payment. Adding just a few more sats (0.0002 BTC) to the payment makes it significantly more likely to be successful.

Collect emails in the checkout flow to process underpayment returns and/or top-ups

Collection of customer emails as part of your checkout will allow OpenNode to contact payers about underpayments directly and offer the option to top up or request a refund.

Note: any top-ups must currently be completed within the initial 10-minute window during which the rate was locked.

Underpayments Control Panel

Even if you follow the best practices above, payers may still underpay checkouts from time to time. If any underpayments are active on your account, a banner will appear near the Changelog bell. From here, it is possible to push through underpayments, and send payers reminder emails to complete the underpaid checkout. For more information, check out our blog piece on the Underpayments Control Panel.

Note: If a checkout from any of our E-commerce integrations is underpaid, an email will be automatically sent to the customer.

Have Questions? Let us know!

In the case of any payment discrepancies, OpenNode will respond to merchant inquiries on a case by case basis. You can reach us at support@opennode.com or use the chatbot at the bottom right of any OpenNode page, 24/7.

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