{ "$schema": "../rpc-schema-draft.json", "type": "object", "rpc": "utxopsbt", "title": "Command to populate PSBT inputs from given UTXOs", "description": [ "*utxopsbt* is a low-level RPC command which creates a PSBT using unreserved inputs in the wallet, optionally reserving them as well.", "", "It deliberately mirrors the parameters and output of lightning-fundpsbt(7) except instead of an optional *minconf* parameter to select unreserved outputs from the wallet, it takes a compulsory list of outputs to use." ], "request": { "required": [ "satoshi", "feerate", "startweight", "utxos" ], "additionalProperties": false, "properties": { "satoshi": { "type": "sat_or_all", "description": [ "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": { "type": "feerate", "description": [ "Used for the transaction as initial feerate." ], "default": "*normal*" }, "startweight": { "type": "u32", "description": [ "The weight of the transaction before *fundpsbt* has added any inputs." ] }, "utxos": { "type": "array", "description": [ "An array of `txid:vout`, each of which must be reserved or available." ], "items": { "type": "outpoint" } }, "reserve": { "type": "u32", "description": [ "If not zero, then *reserveinputs* is called (successfully, with *exclusive* true) on the returned PSBT for this number of blocks." ], "default": "72 blocks" }, "reservedok": { "type": "boolean", "description": [ "If set to true, it will also fail if any of the *utxos* are already reserved." ], "default": "false" }, "locktime": { "type": "u32", "description": [ "If not set, it is set to a recent block height." ] }, "min_witness_weight": { "type": "u32", "description": [ "Minimum weight to use for a UTXO's witness. If the actual witness weight is greater than the provided minimum, the actual witness weight will be used." ] }, "excess_as_change": { "type": "boolean", "description": [ "Flag to add a change output for the excess sats." ] }, "opening_anchor_channel": { "added": "v23.08", "type": "boolean", "description": [ "To signel that it needs emergency reserve for anchors so that we can lowball our commitment tx fees, and min-emergency-msat for reserving some sats for closing anchor channels." ] } } }, "response": { "required": [ "psbt", "feerate_per_kw", "estimated_final_weight", "excess_msat" ], "additionalProperties": false, "properties": { "psbt": { "type": "string", "description": [ "Unsigned PSBT which fulfills the parameters given." ] }, "feerate_per_kw": { "type": "u32", "description": [ "The feerate used to create the PSBT, in satoshis-per-kiloweight." ] }, "estimated_final_weight": { "type": "u32", "description": [ "The estimated weight of the transaction once fully signed." ] }, "excess_msat": { "type": "msat", "description": [ "The amount above *satoshi* which is available. This could be zero, or dust; it will be zero if *change_outnum* is also returned." ] }, "change_outnum": { "type": "u32", "description": [ "The 0-based output number where change was placed (only if parameter *excess_as_change* was true and there was sufficient funds)." ] }, "reservations": { "type": "array", "description": [ "If *reserve* was true or a non-zero number, just as per lightning- reserveinputs(7)." ], "items": { "type": "object", "required": [ "txid", "vout", "was_reserved", "reserved", "reserved_to_block" ], "additionalProperties": false, "properties": { "txid": { "type": "txid", "description": [ "The txid of the transaction." ] }, "vout": { "type": "u32", "description": [ "The 0-based output number." ] }, "was_reserved": { "type": "boolean", "description": [ "Whether this output was previously reserved." ] }, "reserved": { "type": "boolean", "enum": [ true ], "description": [ "Whether this output is now reserved." ] }, "reserved_to_block": { "type": "u32", "description": [ "The blockheight the reservation will expire." ] } } } } }, "post_return_value_notes": [ "On success, returns the *psbt* it created, 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 *excess_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* or a non-zero number, then a *reservations* array is returned, exactly like *reserveinputs*.", "", "If *excess_as_change* is true and the excess is enough to cover an additional output above the `dust_limit`, then an output is added to the PSBT for the excess amount. The *excess_msat* will be zero. A *change_outnum* will be returned with the index of the change output." ] }, "errors": [ "On error the returned object will contain `code` and `message` properties, with `code` being one of the following:", "", "- -32602: If the given parameters are wrong.", "- -1: Catchall nonspecific error.", "- 301: Insufficient UTXOs to meet *satoshi* value." ], "author": [ "Rusty Russell <> is mainly responsible." ], "see_also": [ "lightning-fundpsbt(7)" ], "resources": [ "Main web site: " ], "examples": [ { "request": { "id": "example:utxopsbt#1", "method": "utxopsbt", "params": [ 1000000, "15000perkw", 214, [ "bffbd4f5f789765823b7c1c12151797898702c7fe52f1d08ea644308d33c05b3:1" ], null, true, null, null, true ] }, "response": { "psbt": "cHNidP8BAF4CAAAAAbMFPNMIQ2TqCB0v5X8scJh4eVEhwcG3I1h2iff11Pu/AQAAAAD9////AUFZ3AsAAAAAIlEgO+E35aPNS3YQRaiMByjTJDUYNvBO1Z39o3m42EZGUreYAAAAAAEAcQIAAAABl0vCMXO3vKmwYNrBKr0bsVjo7Wmj501PavWRmxX1dywAAAAAAP3///8Ceh/00gAAAAAWABSauB3UBW2CVXly9l1sU6aMmVAq+ADC6wsAAAAAFgAUA8/shxXh9ASjbsAR5COPhjKfkJyXAAAAAQEfAMLrCwAAAAAWABQDz+yHFeH0BKNuwBHkI4+GMp+QnAAA", "feerate_per_kw": 15000, "estimated_final_weight": 657, "excess_msat": 0, "change_outnum": 0, "reservations": [ { "txid": "bffbd4f5f789765823b7c1c12151797898702c7fe52f1d08ea644308d33c05b3", "vout": 1, "was_reserved": true, "reserved": true, "reserved_to_block": 2240 } ] } }, { "request": { "id": "example:utxopsbt#2", "method": "utxopsbt", "params": { "satoshi": 2000000, "feerate": "18750perkw", "startweight": 214, "utxos": [ "bffbd4f5f789765823b7c1c12151797898702c7fe52f1d08ea644308d33c05b3:1" ], "reservedok": true, "excess_as_change": true } }, "response": { "psbt": "cHNidP8BAF4CAAAAAbMFPNMIQ2TqCB0v5X8scJh4eVEhwcG3I1h2iff11Pu/AQAAAAD9////AWINzQsAAAAAIlEgyRg+3pEh88b9FJiCLEenYCcyJ2ackJUIhDusW72BP2iYAAAAAAEAcQIAAAABl0vCMXO3vKmwYNrBKr0bsVjo7Wmj501PavWRmxX1dywAAAAAAP3///8Ceh/00gAAAAAWABSauB3UBW2CVXly9l1sU6aMmVAq+ADC6wsAAAAAFgAUA8/shxXh9ASjbsAR5COPhjKfkJyXAAAAAQEfAMLrCwAAAAAWABQDz+yHFeH0BKNuwBHkI4+GMp+QnAAA", "feerate_per_kw": 18750, "estimated_final_weight": 657, "excess_msat": 0, "change_outnum": 0, "reservations": [ { "txid": "bffbd4f5f789765823b7c1c12151797898702c7fe52f1d08ea644308d33c05b3", "vout": 1, "was_reserved": true, "reserved": true, "reserved_to_block": 2312 } ] } } ] }