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Overview

Turnkey’s Flutter SDK makes it simple to sign messages and transactions using embedded wallets managed by the TurnkeyProvider.

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Signing messages

To sign a message, select a wallet account and call signMessage from the TurnkeyProvider. You can optionally pass in the payload’s encoding and hashFunction if needed.
lib/widgets/sign_message_button.dart
import 'package:flutter/material.dart';
import 'package:provider/provider.dart';
import 'package:turnkey_sdk_flutter/turnkey_sdk_flutter.dart';

class SignMessageButton extends StatelessWidget {
  const SignMessageButton({super.key});

  @override
  Widget build(BuildContext context) {
    final tk = Provider.of<TurnkeyProvider>(context, listen: false);

    Future<void> doSignMessage() async {
      try {
        final wallet = tk.wallets?.first;
        final account = wallet?.accounts.first;


        final message = 'Hello, Turnkey!';
        final signature = await tk.signMessage(
          walletAccount: account,
          message: message,
        );

        debugPrint('Message signature: $signature');
      } catch (e) {
        debugPrint('Sign message failed: $e');
      }
    }

    return ElevatedButton(
      onPressed: doSignMessage,
      child: const Text('Sign Message'),
    );
  }
}

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Signing transactions

To sign transactions, use the signTransaction function. Select a wallet account’s address, prepare an unsigned transaction, and specify a transaction type.
lib/widgets/sign_transaction_button.dart
import 'package:flutter/material.dart';
import 'package:provider/provider.dart';
import 'package:turnkey_sdk_flutter/turnkey_sdk_flutter.dart';

class SignTransactionButton extends StatelessWidget {
  const SignTransactionButton({super.key});

  @override
  Widget build(BuildContext context) {
    final tk = Provider.of<TurnkeyProvider>(context, listen: false);

    Future<void> doSignTransaction() async {
      try {
        final wallet = tk.wallets?.first;
        final account = wallet?.accounts.first;

        final unsignedTx = '0x...'; // unsigned transaction hex
        final signature = await tk.signTransaction(
          signWith: account.address,    // use the address of the wallet account
          unsignedTransaction: unsignedTx,
          transactionType: v1TransactionType.transaction_type_ethereum,
        );

        debugPrint('Tx signature: $signature');
      } catch (e) {
        debugPrint('Sign transaction failed: $e');
      }
    }

    return ElevatedButton(
      onPressed: doSignTransaction,
      child: const Text('Sign Transaction'),
    );
  }
}