[Feature Request] Option to include private route hints in the invoice

Describe the problem/bug When BTCpay Server generates and invoice for a node with private channels, there are no route hints added so the payment cannot be routed.

Your environment

• Version of BTCPay Server: 1.0.4.0
• Deployment method: manual deployment on a RaspiBlitz
• Other relevant environment details: RaspiBlitz 1.4 with LND 0.9.0

Logs (if applicable) Test invoicegenerated by BTCpay (redacted) :

lncli decodepayreq lnbcxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
{
    "destination": "xxxxxxxxxxxxxxxxxxxxxxxx",
    "payment_hash": "xxxxxxxxxxxxxxxxxxxx",
    "num_satoshis": "13844",
    "timestamp": "xxxxxxxxxx",
    "expiry": "899",
    "description": "Paid to test (Order ID: )",
    "description_hash": "",
    "fallback_addr": "",
    "cltv_expiry": "40",
    "route_hints": [
    ],
    "payment_addr": "xxxxxxxxxxxxxxxxxx",
    "num_msat": "13844000",
    "features": {
        "9": {
            "name": "tlv-onion",
            "is_required": false,
            "is_known": true
        },
        "15": {
            "name": "payment-addr",
            "is_required": false,
            "is_known": true
        },
        "17": {
            "name": "multi-path-payments",
            "is_required": false,
            "is_known": true
        }
    }
}

Invoice created in the command line with lncli addinvoice 1 (redacted):

$ lncli decodepayreq xxxxxxxxxxxxxxxxxxxxxxxxxxx
{
    "destination": "xxxxxxxxxxxxxx",
    "payment_hash": "xxxxxxxxxxxxxx",
    "num_satoshis": "1",
    "timestamp": "xxxxxxxxxx",
    "expiry": "3600",
    "description": "",
    "description_hash": "",
    "fallback_addr": "",
    "cltv_expiry": "40",
    "route_hints": [
        {
            "hop_hints": [
                {
                    "node_id": "xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx",
                    "chan_id": "xxxxxxxxxxxx",
                    "fee_base_msat": 1000,
                    "fee_proportional_millionths": 1,
                    "cltv_expiry_delta": 40
                }
            ]
        }
    ],
    "payment_addr": "xxxxxxxxxxxxxxxxxxxxxxxxxxxxx",
    "num_msat": "1000",
    "features": {
        "9": {
            "name": "tlv-onion",
            "is_required": false,
            "is_known": true
        },
        "15": {
            "name": "payment-addr",
            "is_required": false,
            "is_known": true
        },
        "17": {
            "name": "multi-path-payments",
            "is_required": false,
            "is_known": true
        }
    }
}

To Reproduce Generate invoice on a node with private channels only .

Expected behavior Being able to pay.

Actual behavior Failed to send payment: unable to find path to the destination.

Screenshots/Links REST API format of route hints: https://api.lightning.community/rest/index.html#routehint

Additional context It is a good privacy feature to run a lightning node with private channels only. In that case the pubkey and channels are only advertised to the payer and not publicly.

[bolatovumar]

This is what Zap wallet shows when you are creating a Lightning invoice. Notice the “Include routing hints” toggle. There is also a tooltip element that explains why you would want to enable it.

[rockstardev]

I’m on this.