Build a PSBT

Construct an unsigned Partially Signed Bitcoin Transaction (PSBT) for later signing.

DynamicSDK.instance.bitcoin.buildPsbt constructs an unsigned PSBT without broadcasting it. Use it when you need to inspect, modify, batch, or co-sign a transaction before sending. See What is a PSBT? in the overview for context.

Example

import 'package:dynamic_sdk/dynamic_sdk.dart';

final sdk = DynamicSDK.instance;
final wallet = sdk.wallets.userWallets.firstWhere(
  (w) => w.chain == 'BTC',
);

final unsignedPsbt = await sdk.bitcoin.buildPsbt(
  walletId: wallet.id,
  recipientAddress: 'bc1qxy2kgdygjrsqtzq2n0yrf2493p83kkfjhx0wlh',
  amount: '10000',         // satoshis
  feePriority: 'medium',
);
print('Unsigned PSBT (base64): $unsignedPsbt');

Parameters

Parameter	Type	Description
walletId	String	The id of a wallet whose chain == 'BTC'.
recipientAddress	String	Destination address.
amount	String	Amount in satoshis, encoded as a string to preserve precision.
feePriority	String?	Fee tier: 'high', 'medium', or 'low'.

Returns

Future<String> — the unsigned PSBT, base64-encoded. Pass it to signPsbt to sign, then to sendRawTransaction to broadcast.

Build → sign → broadcast

final unsignedPsbt = await sdk.bitcoin.buildPsbt(
  walletId: wallet.id,
  recipientAddress: 'bc1q...',
  amount: '5000',
);

final signedPsbt = await sdk.bitcoin.signPsbt(
  walletId: wallet.id,
  request: {'unsignedPsbtBase64': unsignedPsbt},
);

final txId = await sdk.bitcoin.sendRawTransaction(
  walletId: wallet.id,
  rawTransaction: signedPsbt,
);
print('Sent: $txId');