diff --git a/README.md b/README.md index 9dedc11..5f5700b 100644 --- a/README.md +++ b/README.md @@ -149,7 +149,7 @@ USAGE: DESCRIPTION: - Attempts loop out the target amount into either the backing lnd's + Attempts to loop out the target amount into either the backing lnd's wallet, or a targeted address. The amount is to be specified in satoshis. @@ -158,9 +158,12 @@ DESCRIPTION: specified. If not specified, a new wallet address will be generated. OPTIONS: - --channel value the 8-byte compact channel ID of the channel to loop out (default: 0) - --addr value the optional address that the looped out funds should be sent to, if left blank the funds will go to lnd's wallet - --amt value the amount in satoshis to loop out (default: 0) + --channel value the 8-byte compact channel ID of the channel to loop out (default: 0) + --addr value the optional address that the looped out funds should be sent to, if let blank the funds will go to lnd's wallet + --amt value the amount in satoshis to loop out (default: 0) + --conf_target value the number of blocks from the swap initiation height that the on-chain HTLC should be swept within (default: 6) + --max_swap_routing_fee value the max off-chain swap routing fee in satoshis, if not specified, a default max fee will be used (default: 0) + --fast Indicate you want to swap immediately, paying potentially a higher fee. If not set the swap server might choose to wait up to 30 minutes before publishing the swap HTLC on-chain, to save on its chain fees. Not setting this flag therefore might result in a lower swap fee. ``` It's possible to receive more inbound capacity on a particular channel @@ -178,6 +181,79 @@ swap is initiated successfully, `loopd` will see the process through. To query in-flight swap statuses, run `loop monitor`. +### Fees explained + +The following is an example output of a 0.01 BTC fast (non-batched) Loop Out +swap from `testnet`: + +```bash +$ loop out --amt 1000000 --fast +Max swap fees for 1000000 sat Loop Out: 36046 sat +Fast swap requested. +CONTINUE SWAP? (y/n), expand fee detail (x): x + +Estimated on-chain sweep fee: 149 sat +Max on-chain sweep fee: 14900 sat +Max off-chain swap routing fee: 20010 sat +Max off-chain prepay routing fee: 36 sat +Max no show penalty (prepay): 1337 sat +Max swap fee: 1100 sat +CONTINUE SWAP? (y/n): +``` + +Explanation: + +- **Max swap fees for sat Loop Out** (36046 sat): The absolute maximum in + fees that need to be paid. This includes on-chain and off-chain fees. This + represents the ceiling or worst-case scenario. The actual fees will likely be + lower. This is the sum of `14900 + 20010 + 36 + 1100` (see below). +- **Estimated on-chain sweep fee** (149 sat): The estimated cost to sweep the + HTLC in case of success, calculated based on the _current_ on-chain fees. + This value is called `miner_fee` in the gRPC/REST responses. +- **Max on-chain sweep fee** (14900 sat): The maximum on-chain fee the daemon + is going to allow for sweeping the HTLC in case of success. A fee estimation + based on the `--conf_target` flag is always performed before sweeping. The + factor of `100` times the estimated fee is applied in case the fees spike + between the time the swap is initiated and the time the HTLC can be swept. But + that is the absolute worst-case fee that will be paid. If there is no fee + spike, a normal, much lower fee will be used. +- **Max off-chain swap routing fee** (20010 sat): The maximum off-chain + routing fee that the daemon should pay when finding a route to pay the + Lightning invoice. This is a hard limit. If no route with a lower or equal fee + is found, the payment (and the swap) is aborted. This value is calculated + statically based on the swap amount (see `maxRoutingFeeBase` and + `maxRoutingFeeRate` in `cmd/loop/main.go`). +- **Max off-chain prepay routing fee** (36 sat): The maximum off-chain routing + fee that the daemon should pay when finding a route to pay the prepay fee. + This is a hard limit. If no route with a lower or equal fee is found, the + payment (and the swap) is aborted. This value is calculated statically based + on the prepay amount (see `maxRoutingFeeBase` and `maxRoutingFeeRate` in + `cmd/loop/main.go`). +- **Max no show penalty (prepay)** (1337 sat): This is the amount that has to be + pre-paid (off-chain) before the server publishes the HTLC on-chain. This is + necessary to ensure the server's on-chain fees are paid if the client aborts + and never completes the swap _after_ the HTLC has been published on-chain. + If the swap completes normally, this amount is counted towards the full swap + amount and therefore is actually a pre-payment and not a fee. This value is + called `prepay_amt` in the gRPC/REST responses. +- **Max swap fee** (1100 sat): The maximum amount of service fees we allow the + server to charge for executing the swap. The client aborts the swap if the + fee proposed by the server exceeds this maximum. It is therefore recommended + to obtain the maximum by asking the server for a quote first. The actual fees + might be lower than this maximum if user specific discounts are applied. This + value is called `swap_fee` in the gRPC/REST responses. + +#### Fast vs. batched swaps + +By default, Loop Outs are executed as normal speed swaps. This means the server +will wait up to 30 minutes until it publishes the HTLC on-chain to improve the +chances that it can be batched together with other user's swaps to reduce the +on-chain footprint and fees. The server offers a reduced swap fee for slow swaps +to incentivize users to batch more. + +If a swap should be executed immediately, the `--fast` flag can be used. Fast +swaps won't benefit from a reduced swap fee. + ### Loop In Swaps Additionally, Loop In is now also supported for mainnet as well. A Loop In swap @@ -195,9 +271,10 @@ DESCRIPTION: Send the amount in satoshis specified by the amt argument off-chain. OPTIONS: - --amt value the amount in satoshis to loop in (default: 0) - --external expect htlc to be published externally - --conf_target the confirmation target for the on chain htlc, if not being published externally + --amt value the amount in satoshis to loop in (default: 0) + --external expect htlc to be published externally + --conf_target value the target number of blocks the on-chain htlc broadcast by the swap client should confirm within (default: 0) + --last_hop value the pubkey of the last hop to use for this swap ``` The `--external` argument allows the on-chain HTLC transacting to be published @@ -208,6 +285,34 @@ A Loop In swap can be executed a follows: ``` loop in ``` + +#### Fees explained + +The following is an example output of a 0.01 BTC Loop In swap from `testnet`: + +```bash +$ loop in --amt 1000000 +Max swap fees for 1000000 sat Loop In: 1562 sat +CONTINUE SWAP? (y/n), expand fee detail (x): x + +Estimated on-chain HTLC fee: 154 sat +Max swap fee: 1100 sat +CONTINUE SWAP? (y/n): +``` + +Explanation: + +- **Estimated on-chain HTLC fee** (154 sat): The estimated on-chain fee that the + daemon has to pay to publish the HTLC. This is an estimation from `lnd`'s + wallet based on the available UTXOs and current network fees. This value is + called `miner_fee` in the gRPC/REST responses. +- **Max swap fee** (1100 sat): The maximum amount of service fees we allow the + server to charge for executing the swap. The client aborts the swap if the + fee proposed by the server exceeds this maximum. It is therefore recommended + to obtain the maximum by asking the server for a quote first. The actual fees + might be lower than this maximum if user specific discounts are applied. This + value is called `swap_fee` in the gRPC/REST responses. + ## Resume When `loopd` is terminated (or killed) for whatever reason, it will pickup @@ -220,4 +325,3 @@ Its location is `~/.loopd//loop.db`. It is possible to execute multiple swaps simultaneously. Just keep loopd running. -