Channel Rebalancing

TL;DR

Use send_payment with allow_self_payment: true for automatic rebalancing, or build_router + send_payment_with_router for manual control over which channels to rebalance.

Channel rebalancing lets you shift liquidity between your channels without opening or closing any channel. It works by sending a circular payment — funds flow out through one channel and back in through another. Your total balance stays the same; only routing fees paid to intermediate nodes are deducted.

When to Rebalance

Suppose you have two channels:

You --[Channel A]--> Peer A    (local: 90, remote: 10)
You --[Channel B]--> Peer B    (local: 10, remote: 90)

Channel A is mostly on your side (outbound-heavy), while Channel B is mostly on the remote side (inbound-heavy). You cannot send payments through Channel B because you have almost no local balance there. A rebalance can even them out.

Two Methods

Method 1: Automatic Routing (send_payment)

Set target_pubkey to your own node pubkey with allow_self_payment: true. The routing algorithm automatically finds a circular path.

{
  "jsonrpc": "2.0",
  "method": "send_payment",
  "params": [
    {
      "target_pubkey": "<your_own_pubkey>",
      "amount": "0x5F5E100",
      "keysend": true,
      "allow_self_payment": true
    }
  ],
  "id": 1
}

Pros: Simple, no need to manually plan the route.

Cons: You cannot control which channels the payment flows through. Not compatible with trampoline routing.

Method 2: Manual Routing (build_router + send_payment_with_router)

This gives you full control over the exact path. Use it when you want to target specific channels for rebalancing.

Step 1 — Build a circular route with build_router:

{
  "jsonrpc": "2.0",
  "method": "build_router",
  "params": [
    {
      "amount": "0x5F5E100",
      "hops_info": [
        { "pubkey": "<peer_A_pubkey>" },
        { "pubkey": "<peer_B_pubkey>" },
        { "pubkey": "<your_own_pubkey>" }
      ]
    }
  ],
  "id": 1
}

Step 2 — Send the payment with the constructed route:

{
  "jsonrpc": "2.0",
  "method": "send_payment_with_router",
  "params": [
    {
      "router": "<router_hops from step 1>",
      "keysend": true
    }
  ],
  "id": 2
}

Pros: Full control over which channels are used. You can also pin specific channels by providing channel_outpoint in hops_info.

Cons: Requires you to know the network topology and plan the route.

Tips

• Use dry_run: true first to verify the route is valid and check the fee before actually sending.
• The rebalance amount plus routing fees must not exceed your local balance in the outbound channel.
• Routing fees depend on the intermediate nodes' fee policies. You can set max_fee_amount to cap the total fee.
• After a successful rebalance, use list_channels to verify the updated balances.