Add PPM toggle for channel fees #3588

kunal-595 · 2026-01-24T10:18:58Z

fixes #1411
Adds a toggle to switch between percentage and PPM input for fee rate when setting channel fees. Only shows for LND-based backends since CLN already uses PPM natively

gemini-code-assist · 2026-01-24T10:19:15Z

Summary of Changes

Hello @kunal-595, I'm Gemini Code Assist¹! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This pull request significantly improves the user experience for setting channel fees by introducing a flexible input mechanism. Users can now choose to specify fee rates in either traditional percentages or the more granular Parts Per Million (PPM), a common unit in the Lightning Network. This enhancement is specifically tailored for LND-based backends, providing a more intuitive and aligned interface for managing channel liquidity.

Highlights

Enhanced Fee Input: Introduced a toggle to switch between percentage and Parts Per Million (PPM) input for channel fee rates, providing more flexibility for users.
LND-Specific Functionality: The PPM toggle is exclusively displayed for LND-based backends, as CLN (c-lightning) already handles PPM natively, streamlining the interface for relevant users.
Dynamic UI Updates: The fee rate input field's placeholder and label dynamically adjust to reflect the currently selected fee rate mode (percentage or PPM), improving user clarity.
Backend Conversion Logic: The FeeStore now includes logic to convert PPM values to percentages before sending them to LND, ensuring correct fee application and compatibility.

Using Gemini Code Assist

The full guide for Gemini Code Assist can be found on our documentation page, here are some quick tips.

Invoking Gemini

You can request assistance from Gemini at any point by creating a comment using either /gemini <command> or @gemini-code-assist <command>. Below is a summary of the supported commands on the current page.

Feature	Command	Description
Code Review	`/gemini review`	Performs a code review for the current pull request in its current state.
Pull Request Summary	`/gemini summary`	Provides a summary of the current pull request in its current state.
Comment	@gemini-code-assist	Responds in comments when explicitly tagged, both in pull request comments and review comments.
Help	`/gemini help`	Displays a list of available commands.

Customization

To customize Gemini Code Assist for GitHub experience, repository maintainers can create a configuration file and/or provide a custom code review style guide (such as PEP-8 for Python) by creating and adding files to a .gemini/ folder in the base of the repository. Detailed instructions can be found here.

Limitations & Feedback

Gemini Code Assist may make mistakes. Please leave feedback on any instances where its feedback is incorrect or counter productive. You can react with 👍 and 👎 on @gemini-code-assist comments. If you're interested in giving your feedback about your experience with Gemini Code Assist for Github and other Google products, sign up here.

You can also get AI-powered code generation, chat, as well as code reviews directly in the IDE at no cost with the Gemini Code Assist IDE Extension.

Review the Privacy Notices, Generative AI Prohibited Use Policy, Terms of Service, and learn how to configure Gemini Code Assist in GitHub here. Gemini can make mistakes, so double check it and use code with caution. ↩

gemini-code-assist

Code Review

This pull request adds a useful toggle for setting channel fees in either percentage or PPM for LND-based backends. The implementation is mostly correct, but a critical issue in the fee rate conversion logic was found that would lead to incorrect and excessively high fees being set. The detailed comment provides the fix.

gemini-code-assist · 2026-01-24T10:21:10Z

stores/FeeStore.ts

+        // convert PPM to percentage for LND
+        if (feeRateMode === 'ppm' && BackendUtils.isLNDBased()) {
+            feeRate = new BigNumber(feeRate).dividedBy(10000).toString();
+        }


The conversion from PPM to the decimal fee rate for LND is incorrect. You are dividing by 10000, but it should be 1000000 to convert from Parts Per Million to a decimal rate.

For example, a 1000 PPM fee rate should be converted to 0.001 for the LND API. Your current implementation would convert it to 0.1, which is 100x larger and would result in a 10% fee, which is extremely high.

The comment is also a bit misleading. It's not converting to a percentage, but rather to a decimal fee rate that LND expects.

Here is the suggested correction:

Suggested change

// convert PPM to percentage for LND

if (feeRateMode === 'ppm' && BackendUtils.isLNDBased()) {

feeRate = new BigNumber(feeRate).dividedBy(10000).toString();

}

// convert PPM to decimal rate for LND

if (feeRateMode === 'ppm' && BackendUtils.isLNDBased()) {

feeRate = new BigNumber(feeRate).dividedBy(1000000).toString();

}

Copilot

Pull request overview

This PR adds a toggle to switch between percentage and PPM (parts per million) input modes for channel fee rates when setting fees. The toggle is only displayed for LND-based backends since Core Lightning (CLN) natively uses PPM units.

Changes:

Added PPM to percentage conversion logic in the fee store
Implemented a toggle button UI component to switch between percentage and PPM input modes
Updated labels and placeholders to reflect the selected unit mode

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.

File	Description
stores/FeeStore.ts	Added feeRateMode parameter and PPM-to-percentage conversion logic for LND backends
components/SetFeesForm.tsx	Added toggle button UI, updated labels/placeholders based on mode, and integrated mode selection with fee submission

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.

Copilot · 2026-01-24T10:23:24Z

stores/FeeStore.ts

+        let feeRate = newFeeRate.replace(/,/g, '.');
+
+        // convert PPM to percentage for LND
+        if (feeRateMode === 'ppm' && BackendUtils.isLNDBased()) {


The conversion from PPM to percentage should handle empty or invalid input strings. When feeRate is an empty string, calling new BigNumber(feeRate) will throw an error. Consider adding a check to only perform the conversion when feeRate is non-empty: if (feeRateMode === 'ppm' && BackendUtils.isLNDBased() && feeRate) {

Suggested change

if (feeRateMode === 'ppm' && BackendUtils.isLNDBased()) {

if (feeRateMode === 'ppm' && BackendUtils.isLNDBased() && feeRate) {

kaloudis · 2026-01-24T14:59:04Z

I think we'd want to set up some sort of utility for this in FeeUtils with corresponding tests

kunal-595 · 2026-01-26T04:06:47Z

Sounds good, i will move that PPM → % logic into FeeUtils, add some unit tests, and update the store, pushing shortly.

kaloudis · 2026-01-28T05:36:46Z

Looking mostly solid so far. Even if CLNRest uses PPM by default, you should be able to toggle between the two modes with it.

I think the next step after that would be being able to toggle between the units on the FeeBreakdown component

kunal-595 · 2026-01-28T14:12:44Z

That makes sense, i will hook that up in FeeBreakdown so users can switch modes on the fly, i will ping you here once i have pushed the update to the branch.

Add PPM toggle for channel fees

a5c85ff

Copilot AI review requested due to automatic review settings January 24, 2026 10:18

Copilot started reviewing on behalf of kunal-595 January 24, 2026 10:19 View session

gemini-code-assist bot reviewed Jan 24, 2026

View reviewed changes

Copilot AI reviewed Jan 24, 2026

View reviewed changes

Fix PPM to decimal rate conversion

47b4d89

Add ppmToPercent utility to FeeUtils

74380ea

kaloudis added Channels Fees labels Jan 28, 2026

Provide feedback

Saved searches

Use saved searches to filter your results more quickly

Uh oh!

Add PPM toggle for channel fees #3588

Add PPM toggle for channel fees #3588

kunal-595 commented Jan 24, 2026

Uh oh!

gemini-code-assist bot commented Jan 24, 2026

Uh oh!

gemini-code-assist bot left a comment

Uh oh!

gemini-code-assist bot Jan 24, 2026

Uh oh!

Copilot AI left a comment

Uh oh!

Copilot AI Jan 24, 2026

Uh oh!

kaloudis commented Jan 24, 2026

Uh oh!

kunal-595 commented Jan 26, 2026

Uh oh!

kaloudis commented Jan 28, 2026

Uh oh!

kunal-595 commented Jan 28, 2026

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

2 participants

	if (feeRateMode === 'ppm' && BackendUtils.isLNDBased()) {
	if (feeRateMode === 'ppm' && BackendUtils.isLNDBased() && feeRate) {

Uh oh!

Add PPM toggle for channel fees #3588

Are you sure you want to change the base?

Add PPM toggle for channel fees #3588

Conversation

kunal-595 commented Jan 24, 2026

Uh oh!

gemini-code-assist bot commented Jan 24, 2026

Summary of Changes

Highlights

Footnotes

Uh oh!

gemini-code-assist bot left a comment

Choose a reason for hiding this comment

Code Review

Uh oh!

gemini-code-assist bot Jan 24, 2026

Choose a reason for hiding this comment

Uh oh!

Copilot AI left a comment

Choose a reason for hiding this comment

Pull request overview

Reviewed changes

Uh oh!

Copilot AI Jan 24, 2026

Choose a reason for hiding this comment

Uh oh!

kaloudis commented Jan 24, 2026

Uh oh!

kunal-595 commented Jan 26, 2026

Uh oh!

kaloudis commented Jan 28, 2026

Uh oh!

kunal-595 commented Jan 28, 2026

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

2 participants