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LIGHTNING-FUNDPSBT(7)	      lightning-fundpsbt	 LIGHTNING-FUNDPSBT(7)

       lightning-fundpsbt - Command to populate	PSBT inputs from the wallet

       fundpsbt	satoshi	feerate	startweight [minconf] [reserve]	[locktime]

       fundpsbt	 is  a	low-level RPC command which creates a PSBT using unre-
       served inputs in	the wallet, optionally reserving them as well.

       satoshi is the minimum satoshi value of the output(s)  needed  (or  the
       string "all" meaning use	all unreserved inputs).	 If a value, 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.

       feerate	can be one of the feerates listed in lightning-feerates(7), or
       one of the strings urgent (aim for next block), normal (next  4	blocks
       or so) or slow (next 100	blocks or so) to use lightningdas internal es-
       timates.	 It can	also be	a feerate is a number, with an	optional  suf-
       fix:  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.

       startweight  is the weight of the transaction before fundpsbt has added
       any inputs.

       minconf specifies the minimum number of confirmations that used outputs
       should have. Default is 1.

       reserve	is  a  boolean:	 if  true (the default), then reserveinputs is
       called (successfully, with exclusive true) on the returned PSBT.

       locktime	is an optional locktime: if not	set, it	is  set	 to  a	recent
       block height.

       Let's assume the	caller is trying to produce a 100,000 satoshi output.

       First,  the  caller estimates the weight	of the core (typically 42) and
       known outputs of	the transaction	(typically (9 +	scriptlen) * 4).   For
       a simple	P2WPKH it's a 22 byte scriptpubkey, so that's 124 weight.

       It calls	"fundpsbt 100000sat slow 166", which succeeds, and returns the
       psbt and	feerate_per_kw it used,	the estimated_final_weight and any ex-

       If  excess_msat is greater than the cost	of adding a change output, the
       caller adds a change output randomly to position	0 or 1	in  the	 PSBT.
       Say  feerate_per_kw  is	253, and the change output is a	P2WPKH (weight
       124), the cost is around	31 sats.  With the dust	limit disallowing pay-
       ments  below  546 satoshis, we would only create	a change output	if ex-
       cess_msat was greater or	equal to 31 + 546.

       On success, returns the	psbt  containing  the  inputs,	feerate_per_kw
       showing	the  exact numeric feerate it used, estimated_final_weight for
       the estimated weight of the transaction	once  fully  signed,  and  ex-
       cess_msat containing the	amount above satoshi which is available.  This
       could be	zero, or dust.	If satoshi was "all", then excess_msat is  the
       entire  amount  once  fees are subtracted for the weights of the	inputs
       and startweight.

       If reserve was true, then a reservations	 array	is  returned,  exactly
       like reserveinputs.

       On  error the returned object will contain code and message properties,
       with code being one of the following:

	      o	     -32602: If	the given parameters are wrong.

	      o	     -1: Catchall nonspecific error.

	      o	     301: Insufficient UTXOs to	meet satoshi value.

       Rusty Russell> is	mainly responsible.

       lightning-utxopsbt(7),	lightning-reserveinputs(7),    lightning-unre-

       Main web	site:



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