Build, sign, broadcast Bitcoin transactions, and compute signature hashes with Zafeguard Bitcoin components.

Bitcoin Transactions

Components for building, signing, and broadcasting Bitcoin transactions, plus signature hash computation.

Public endpoints enforce rate limits per IP address and can fail under concurrent load. Use a private or self-hosted Bitcoin node. See Connecting to Bitcoin.

BROADCAST_BITCOIN_TRANSACTION

BROADCAST_BITCOIN_TRANSACTION Workflow Component

Broadcasts a finalized raw transaction to the Bitcoin network and returns the transaction ID.

Config

Field	Type	Required	Description
`network`	`'mainnet' \| 'testnet'`	Yes	Target Bitcoin network

Inputs

Field	Type	Description
`signedTransaction`	`string` (hex)	Raw transaction hex to broadcast

Outputs

Field	Type	Description
`txid`	`string`	Transaction ID (64-char hex)

SDK example

import { WorkspaceClient, ComponentModule } from '@zafeguard/caller-sdk';
const workspace = new WorkspaceClient({ apiKey: process.env.ZAFEGUARD_API_KEY! });

const result = await workspace.call(ComponentModule.BROADCAST_BITCOIN_TRANSACTION, {
  signedTransaction: 'deadbeef...',
}).promise();
console.log(result.txid);

BUILD_BITCOIN_TRANSACTION

BUILD_BITCOIN_TRANSACTION Workflow Component

Builds an unsigned PSBT with UTXO selection, fee estimation, and sighash generation. Supports optional locktime, OP_RETURN data, change address configuration, and fee deduction.

Config

Field	Type	Required	Default	Description
`paymentType`	`'p2pkh' \| 'p2sh-p2wpkh' \| 'p2wpkh' \| 'p2tr'`	Yes	—	Bitcoin payment type (address format)
`network`	`'mainnet' \| 'testnet'`	Yes	—	Target Bitcoin network
`deductFee`	`boolean`	No	`false`	When `true`, subtracts the estimated fee from `amount` instead of adding it on top

Inputs

Field	Type	Description
`recipientAddress`	`string`	Destination Bitcoin address
`amount`	`number`	Amount to send in satoshis (non-negative integer)
`publicKey`	`string` (hex)	Sender public key — compressed 33 bytes (66 hex) or uncompressed 65 bytes (130 hex)
`locktime`	`string \| null`	Transaction locktime as block height string. `null` to disable
`opReturnData`	`string \| null`	Hex data to embed in an OP_RETURN output. `null` to skip
`changeAddress`	`string \| null`	Address for change output. `null` uses the sender's address
`feeRate`	`number \| null`	Custom fee rate in sat/vByte. `null` falls back to the network's half-hour fee estimate. Must be a positive number. See Customizing Transaction Fees for the vBytes formula and recommended rate ranges.

Outputs

Field	Type	Description
`unsignedTransaction`	`string` (hex)	Hex-encoded unsigned PSBT
`messageHashes`	`string[]`	Array of sighash hex strings, one per input (each 64 hex chars)
`estimatedFee`	`number`	Estimated network fee in satoshis (using the chosen fee rate)

SDK example

import { WorkspaceClient, ComponentModule } from '@zafeguard/caller-sdk';
const workspace = new WorkspaceClient({ apiKey: process.env.ZAFEGUARD_API_KEY! });

const result = await workspace.call(ComponentModule.BUILD_BITCOIN_TRANSACTION, {
  recipientAddress: 'bc1q...',
  amount: 50000,
  publicKey: '02abc123...',
  locktime: null,
  opReturnData: null,
  changeAddress: null,
  feeRate: null, // or e.g. 25 for 25 sat/vByte
}).promise();
console.log(result.unsignedTransaction);
console.log(result.messageHashes); // sign each of these
console.log(result.estimatedFee);

Field	Type	Description
`unsignedTransaction`	`string` (hex)	Hex-encoded PSBT from `BUILD_BITCOIN_TRANSACTION`
`signatures`	`string[]`	Hex-encoded signatures, one per input
`publicKey`	`string` (hex)	Signer public key — compressed 33 bytes (66 hex) or uncompressed 65 bytes (130 hex)

Outputs

Field	Type	Description
`signedTransaction`	`string` (hex)	Finalized raw transaction hex, ready to broadcast

SDK example

import { WorkspaceClient, ComponentModule } from '@zafeguard/caller-sdk';
const workspace = new WorkspaceClient({ apiKey: process.env.ZAFEGUARD_API_KEY! });

const result = await workspace.call(ComponentModule.SIGN_BITCOIN_TRANSACTION, {
  unsignedTransaction: buildResult.unsignedTransaction,
  signatures: ['3045...', '3044...'],
  publicKey: '02abc123...',
}).promise();
console.log(result.signedTransaction);

COMPUTE_BITCOIN_SIGNATURE_HASH

COMPUTE_BITCOIN_SIGNATURE_HASH Workflow Component

Computes a signature hash for a message using either the standard Bitcoin message format or raw SHA-256 hashing.

Config

Field	Type	Required	Description
`format`	`'bitcoin-message' \| 'raw'`	Yes	`bitcoin-message` produces a standard signed-message hash. `raw` produces a double SHA-256 hash

Inputs

Field	Type	Description
`message`	`string`	Message string to hash

Outputs

Field	Type	Description
`messageHash`	`string`	32-byte hash as 64-char hex, ready for external signing

Transaction flow

GET_BITCOIN_DERIVATION_PATH
         │
         ▼
  (external signing)
  → public key
         │
         ▼
BUILD_BITCOIN_TRANSACTION ─── messageHashes ──▶ (external signing)
         │                                              │ signatures
         │                                              ▼
         └─── unsignedTransaction ──▶ SIGN_BITCOIN_TRANSACTION
                                               │
                                               ▼ signedTransaction
                                   BROADCAST_BITCOIN_TRANSACTION

Stage statuses

Status	Meaning
`CREATED`	Queued, waiting to execute
`RUNNING`	Actively executing
`COMPLETED`	Finished successfully
`FAILED`	Failed — check `error` field

Bitcoin Transactions

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