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Bitcoin Core combinepsbt — Merge Multiple PSBTs
x402
Bitcoin Core combinepsbt — Merge Multiple PSBTs is a paid API for AI agents from x402.chainquery.com, paid per call via x402, $0.005/call, status unknown (last checked 2026-09-15).
Merges multiple Partially Signed Bitcoin Transactions (PSBTs) for the same underlying transaction into a single combined PSBT
Price / call$0.005
Success—
StatusUnknown
How this service works
chainquery Bitcoin RPC: pay-per-call Bitcoin Core over x402, no API key. Merge multiple PSBTs for the same transaction into one. Bitcoin Core combinepsbt.
Output
Returns the combined PSBT as a base64-encoded string with all partial signatures and inputs from the provided PSBTs merged into one, ready for further signing or finalization.
Example use cases
Aggregate signatures from multisig co-signers
“I'm coordinating a 3-of-5 multisig transaction and I've collected PSBTs from three different signers so far. Can you merge all three of them together into one combined PSBT? Here are the base64 strings: ["cHNidP8BA...", "cHNidP8BB...", "cHNidP8BC..."]”
Consolidate hardware wallet signing rounds
“We're doing a two-round signing process with hardware wallets for security. I've got the PSBT after the first hardware wallet signed it, and now the second one has signed their copy. Can you combine both of these signed PSBTs into a single transaction? ["cHNidP8BA...", "cHNidP8BB..."]”
Merge CoinJoin participant signatures
“We're running a CoinJoin transaction with five participants and each one has returned their partially signed PSBT. I need to merge all five of these signatures into one unified PSBT before we broadcast. Can you combine them for me? ["cHNidP8BA...", "cHNidP8BB...", "cHNidP8BC...", "cHNidP8BD...", "cHNidP8BE..."]”
Technical details
Endpoint
GEThttps://x402.chainquery.com/v1/rpc/combinepsbtWhen to prefer
Use this endpoint when you need to merge partial signatures from multiple signers (e.g. multisig wallets, hardware wallets, CoinJoin participants) into one PSBT without running your own Bitcoin Core node. Prefer this over joinpsbts, which is for combining PSBTs for different transactions rather than merging signatures for the same transaction.
Side effects
- PSBTs do not correspond to the same underlying transaction — Bitcoin Core returns an error
- Invalid base64 PSBT encoding — parse error from Bitcoin Core
- Empty or single-element PSBT array — may return error or passthrough
- params query param is not valid JSON — 400 or RPC error
- Payment not completed over x402 — 402 payment required response
- Node unavailable — 503 or timeout
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| inputrequired | object | |
| output | object |
Tags
x402
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