Sign messages - Phantom developer documentation

The Phantom Connect React Native SDK provides chain-specific hooks (useSolana and useEthereum) for signing messages optimized for mobile platforms.

Chain-specific message signing hooks

These examples copy signatures with expo-clipboard, and the Solana example encodes signatures with bs58. Install both before running the examples:

npx expo install expo-clipboard
npm install bs58

Solana message signing (useSolana)

import React, { useState } from "react";
import { View, Button, TextInput, Alert, Text, StyleSheet } from "react-native";
import * as Clipboard from "expo-clipboard";
import bs58 from "bs58";
import { useSolana } from "@phantom/react-native-sdk";

function SolanaMessageSigning() {
  const { solana } = useSolana();
  const [message, setMessage] = useState("Hello from Solana!");
  const [isLoading, setIsLoading] = useState(false);

  const handleSign = async () => {
    if (!message.trim()) {
      Alert.alert("Error", "Please enter a message");
      return;
    }

    setIsLoading(true);
    try {
      // signature is a Uint8Array; encode it before displaying or copying
      const { signature } = await solana.signMessage(message);
      const encodedSignature = bs58.encode(signature);
      Alert.alert(
        "Message Signed!",
        `Signature: ${encodedSignature.slice(0, 20)}...`,
        [
          { text: "Copy", onPress: () => Clipboard.setStringAsync(encodedSignature) },
          { text: "OK" },
        ]
      );
    } catch (error) {
      const errorMessage = error instanceof Error ? error.message : String(error);
      Alert.alert("Error", `Signing failed: ${errorMessage}`);
    } finally {
      setIsLoading(false);
    }
  };

  return (
    <View style={styles.container}>
      <Text style={styles.title}>Sign Solana Message</Text>
      
      <TextInput
        style={styles.input}
        placeholder="Enter message to sign"
        value={message}
        onChangeText={setMessage}
        multiline
      />
      
      <Button
        title={isLoading ? "Signing..." : "Sign Message"}
        onPress={handleSign}
        disabled={isLoading}
      />
    </View>
  );
}

const styles = StyleSheet.create({
  container: { padding: 20, gap: 12 },
  title: { fontSize: 18, fontWeight: "600" },
  input: { borderWidth: 1, borderColor: "#ccc", borderRadius: 8, padding: 12, minHeight: 80 },
});

Ethereum message signing (useEthereum)

Ethereum methods aren’t available on React Native yet. The React Native SDK connects only through embedded wallets (Google and Apple social login), and EVM support for embedded wallets is coming soon. See Chain support for current availability.

import React, { useState } from "react";
import { View, Button, TextInput, Alert, Text, StyleSheet } from "react-native";
import * as Clipboard from "expo-clipboard";
import { useEthereum } from "@phantom/react-native-sdk";

function EthereumMessageSigning() {
  const { ethereum } = useEthereum();
  const [message, setMessage] = useState("Hello from Ethereum!");
  const [isLoading, setIsLoading] = useState(false);

  const handleSignPersonal = async () => {
    if (!message.trim()) {
      Alert.alert("Error", "Please enter a message");
      return;
    }

    setIsLoading(true);
    try {
      const accounts = await ethereum.getAccounts();
      const signature = await ethereum.signPersonalMessage(message, accounts[0]);
      
      Alert.alert(
        "Message Signed!",
        `Signature: ${signature.slice(0, 20)}...`,
        [
          { text: "Copy", onPress: () => Clipboard.setStringAsync(signature) },
          { text: "OK" },
        ]
      );
    } catch (error) {
      const errorMessage = error instanceof Error ? error.message : String(error);
      Alert.alert("Error", `Signing failed: ${errorMessage}`);
    } finally {
      setIsLoading(false);
    }
  };

  const handleSignTypedData = async () => {
    setIsLoading(true);
    try {
      const typedData = {
        types: {
          EIP712Domain: [
            { name: "name", type: "string" },
            { name: "version", type: "string" },
            { name: "chainId", type: "uint256" },
          ],
          Message: [
            { name: "content", type: "string" },
          ]
        },
        primaryType: "Message",
        domain: {
          name: "My Mobile App",
          version: "1",
          chainId: 1,
        },
        message: {
          content: message,
        }
      };

      const accounts = await ethereum.getAccounts();
      const signature = await ethereum.signTypedData(typedData, accounts[0]);
      
      Alert.alert(
        "Typed Data Signed!",
        `Signature: ${signature.slice(0, 20)}...`,
        [
          { text: "Copy", onPress: () => Clipboard.setStringAsync(signature) },
          { text: "OK" },
        ]
      );
    } catch (error) {
      const errorMessage = error instanceof Error ? error.message : String(error);
      Alert.alert("Error", `Signing failed: ${errorMessage}`);
    } finally {
      setIsLoading(false);
    }
  };

  return (
    <View style={styles.container}>
      <Text style={styles.title}>Sign Ethereum Message</Text>
      
      <TextInput
        style={styles.input}
        placeholder="Enter message to sign"
        value={message}
        onChangeText={setMessage}
        multiline
      />
      
      <View style={styles.buttonContainer}>
        <Button
          title={isLoading ? "Signing..." : "Sign Personal Message"}
          onPress={handleSignPersonal}
          disabled={isLoading}
        />
        
        <Button
          title={isLoading ? "Signing..." : "Sign Typed Data"}
          onPress={handleSignTypedData}
          disabled={isLoading}
        />
      </View>
    </View>
  );
}

const styles = StyleSheet.create({
  container: { padding: 20, gap: 12 },
  title: { fontSize: 18, fontWeight: "600" },
  input: { borderWidth: 1, borderColor: "#ccc", borderRadius: 8, padding: 12, minHeight: 80 },
  buttonContainer: { gap: 8 },
});