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Charms

Sign and broadcast

The Prover API returns an unsigned Bitcoin transaction — a single transaction that spends the inputs and carries the spell and its proof in an OP_RETURN output. Sign it and broadcast it to complete the transfer.

Sign

Section titled “Sign”

Sign the transaction with the keys for its funding inputs:

Terminal window
bitcoin-cli signrawtransactionwithwallet <spell_tx_hex>

The wallet must be able to sign whatever input types it owns. The Charms tooling and node setup recommend bech32m (Taproot) addresses, so ensure your signing stack supports Taproot / Schnorr signatures. Most modern libraries do — Bitcoin Core, bitcoinjs-lib, rust-bitcoin, btcd, and others.

Broadcast

Section titled “Broadcast”

Send the signed transaction:

Terminal window
bitcoin-cli sendrawtransaction <signed_spell_tx_hex>

Considerations

Section titled “Considerations”
  • Fee rate. The fee is set when you prove (fee_rate in the Prover API request, or --fee-rate on the CLI — default 2.0 sats/vB). Choose a rate appropriate to network conditions so the transaction is accepted into the mempool and confirmed.
  • Validate before sending. Confirm the transaction is well-formed and the inputs are still unspent before broadcasting.
  • One transaction. There is no commit/reveal step — signing and broadcasting the single returned transaction is all that’s needed.