This plugin dynamically adjusts fees according to channel balances. The default behaviour is to automatically adjust fees at startup and following forwarding events. There is a threshold for balance deltas that must be crossed before an update is triggered. It can also set the max htlc for channels according to available liquidity. This may reduce transaction failures but it will also reveal information about what the current channel balance is.

You need uv to run this plugin like a binary. After uv is installed you can simply run

lightning-cli plugin start /path/to/feeadjuster.py

If you use systemd to start CLN, you must have uv in the PATH that systemd uses, which is likely different than the PATH from your shell. Most uv installation methods install uv into your user's home directory (~/.local/bin or ~/.cargo/bin), which systemd cannot access.

You can either:

Option 1: Install uv system-wide (recommended):

curl -LsSf https://astral.sh/uv/install.sh | sudo env UV_INSTALL_DIR="/usr/local/bin" sh

Option 2: Copy your existing user installation:

sudo cp "$(command -v uv)" /usr/local/bin/uv

Option 3: Configure your systemd service to use a custom PATH (see systemd documentation).

To verify uv is accessible to systemd:

sudo systemd-run --user --wait command -v uv

This should output /usr/local/bin/uv.

For general plugin installation instructions see the repos main README.md

• feeadjuster-deactivate-fuzz boolean (default False) deactivates update threshold randomization and hysterisis
• feeadjuster-deactivate-fee-update boolean (default False) deactivates automatic fee updates for forward events
• feeadjuster-threshold default 0.05 - Relative channel balance delta at which to trigger an update. Default 0.05 means 5%. Note: it's also fuzzed by 1.5%.
• feeadjuster-threshold-abs default 0.001btc - Absolute channel balance delta at which to always trigger an update. Note: it's also fuzzed by 1.5%.
• feeadjuster-enough-liquidity default 0msat (turned off) - Beyond this liquidity do not adjust fees. This also modifies the fee curve to achieve having this amount of liquidity.
• feeadjuster-adjustment-method Adjustment method to calculate channel fee. Can be 'default', 'soft' for less difference or 'hard' for higher difference.
• feeadjuster-imbalance default 0.5 (always acts) - Ratio at which channel imbalance the feeadjuster should start acting. Set higher or lower values to limit feeadjuster's activity to more imbalanced channels. E.g. 0.3 for '70/30'% or 0.6 for '40/60'%.
• feeadjuster-feestrategy Sets the per channel fee selection strategy. Can be 'global' (default) to use global config or default values, or 'median' to use the median fees from peers of peer.
• feeadjuster-median-multiplier Sets the factor with which the median fee is multiplied if using the fee strategy 'median'. This allows over- or underbidding other nodes by a constant factor (default: 1.0).
• feeadjuster-max-htlc-steps Default 0 (turned off). Sets the number of max htlc adjustment steps. If our local channel balance drops below a step level it will reduce the max htlc to that level, which can reduce local routing channel failures. A value of 0 disables the stepping.
• feeadjuster-basefee Default False, Also adjust base fee dynamically. Currently only affects median strategy.