lightning-fundchannel – Command for establishing a lightning channel¶
fundchannel id amount [feerate] [announce] [minconf] [utxos] [push_msat] [close_to] [request_amt] [compact_lease]
The fundchannel RPC command opens a payment channel with a peer by
committing a funding transaction to the blockchain as defined in BOLT
If not already connected, fundchannel will automatically attempt
to connect if C-lightning knows a way to contact the node (either from
normal gossip, or from a previous connect call).
This auto-connection can fail if C-lightning does not know how to contact
the target node; see lightning-connect(7).
transaction is confirmed, normal channel operations may begin. Readiness
is indicated by listpeers reporting a state of
for the channel.
id is the peer id obtained from connect.
amount is the amount in satoshis taken from the internal wallet to fund the channel. The string all can be used to specify all available funds (or 16777215 satoshi if more is available and large channels were not negotiated with the peer). Otherwise, it is in satoshi precision; it can be a whole number, a whole number ending in sat, a whole number ending in 000msat, or a number with 1 to 8 decimal places ending in btc. The value cannot be less than the dust limit, currently set to 546, nor more than 16777215 satoshi (unless large channels were negotiated with the peer).
feerate is an optional feerate used for the opening transaction and as initial feerate for commitment and HTLC transactions. It can be one of the strings urgent (aim for next block), normal (next 4 blocks or so) or slow (next 100 blocks or so) to use lightningd’s internal estimates: normal is the default.
Otherwise, feerate is a number, with an optional suffix: perkw means the number is interpreted as satoshi-per-kilosipa (weight), and perkb means it is interpreted bitcoind-style as satoshi-per-kilobyte. Omitting the suffix is equivalent to perkb.
announce is an optional flag that triggers whether to announce this
channel or not. Defaults to
true. An unannounced channel is considered
minconf specifies the minimum number of confirmations that used outputs should have. Default is 1.
utxos specifies the utxos to be used to fund the channel, as an array of “txid:vout”.
push_msat is the amount of millisatoshis to push to the channel peer at open. Note that this is a gift to the peer – these satoshis are added to the initial balance of the peer at channel start and are largely unrecoverable once pushed.
close_to is a Bitcoin address to which the channel funds should be sent to
on close. Only valid if both peers have negotiated
close_to set to closing script iff is negotiated.
request_amt is an amount of liquidity you’d like to lease from the peer.
If peer supports
option_will_fund, indicates to them to include this
much liquidity into the channel. Must also pass in compact_lease.
compact_lease is a compact represenation of the peer’s expected channel lease terms. If the peer’s terms don’t match this set, we will fail to open the channel.
This example shows how to use lightning-cli to open new channel with peer 03f…fc1 from one whole utxo bcc1…39c:0 (you can use listfunds command to get txid and vout):
lightning-cli -k fundchannel id=03f...fc1 amount=all feerate=normal utxos='["bcc1...39c:0"]'
On success, an object is returned, containing:
- tx (hex): The raw transaction which funded the channel
- txid (txid): The txid of the transaction which funded the channel
- outnum (u32): The 0-based output index showing which output funded the channel
- channel_id (hex): The channel_id of the resulting channel (always 64 characters)
- close_to (hex, optional): The raw scriptPubkey which mutual close will go to; only present if close_to parameter was specified and peer supports
The following error codes may occur:
- -1: Catchall nonspecific error.
- 300: The maximum allowed funding amount is exceeded.
- 301: There are not enough funds in the internal wallet (including fees) to create the transaction.
- 302: The output amount is too small, and would be considered dust.
- 303: Broadcasting of the funding transaction failed, the internal call to bitcoin-cli returned with an error.
Failure may also occur if lightningd and the peer cannot agree on channel parameters (funding limits, channel reserves, fees, etc.).
lightning-connect(7), lightning-listfunds(), lightning-listpeers(7), lightning-feerates(7), lightning-multifundchannel(7)