The SignInWithBaseButton is a ready-to-use React component that provides a seamless authentication experience using Base Account. It handles the entire sign-in flow including wallet connection, message signing, and user authentication.

Please Follow the brand guidelines

If you intend on using the SignInWithBaseButton, please follow the Brand Guidelines to ensure consistency across your application.

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Installation

npm install @base-org/account-ui

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Basic Usage

import { SignInWithBaseButton } from '@base-org/account-ui/react';

function LoginForm() {
  const handleSignIn = () => {
    console.log('User clicked sign in');
    // Custom sign-in logic here
  };

  return (
    <SignInWithBaseButton 
      align="center"
      variant="solid"
      colorScheme="light"
      onClick={handleSignIn}
    />
  );
}

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Props

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Styling Props

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align
'left' | 'center' | 'right'

Button alignment within its container (default: ‘left’)

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variant
'solid' | 'transparent'

Button variant style (default: ‘solid’)

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colorScheme
'light' | 'dark' | 'system'

Color scheme for the button appearance (default: ‘system’)

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size
'small' | 'medium' | 'large'

Button size (default: ‘medium’)

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disabled
boolean

Whether the button is disabled (default: false)

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Event Handlers

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onClick
function

Callback function called when the button is clicked

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onSignInResult
function

Callback function called when authentication completes (success or failure)

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Styling Options

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Alignment

{/* Left aligned */}
<SignInWithBaseButton align="left" onClick={handleSignIn} />

{/* Center aligned */}
<SignInWithBaseButton align="center" onClick={handleSignIn} />

{/* Right aligned */}
<SignInWithBaseButton align="right" onClick={handleSignIn} />

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Variants

{/* Solid variant (default) */}
<SignInWithBaseButton variant="solid" onClick={handleSignIn} />

{/* Transparent variant */}
<SignInWithBaseButton variant="transparent" onClick={handleSignIn} />

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Color Schemes

{/* Light theme */}
<SignInWithBaseButton colorScheme="light" onClick={handleSignIn} />

{/* Dark theme */}
<SignInWithBaseButton colorScheme="dark" onClick={handleSignIn} />

{/* System theme (follows user's system preference) */}
<SignInWithBaseButton colorScheme="system" onClick={handleSignIn} />

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Sizes

{/* Different sizes */}
<SignInWithBaseButton size="small" onClick={handleSignIn} />
<SignInWithBaseButton size="medium" onClick={handleSignIn} />
<SignInWithBaseButton size="large" onClick={handleSignIn} />

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Authentication Flow Integration

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Complete Authentication Example

import React, { useState } from 'react';
import { SignInWithBaseButton } from '@base-org/account-ui/react';
import { createBaseAccountSDK, getCryptoKeyAccount } from '@base-org/account';
import { createWalletClient, custom } from 'viem';
import { base } from 'viem/chains';

export default function AuthenticationDemo() {
  const [user, setUser] = useState(null);
  const [loading, setLoading] = useState(false);
  const [error, setError] = useState(null);

  const sdk = createBaseAccountSDK({
    appName: 'Authentication Demo',
    appLogoUrl: 'https://example.com/logo.png',
    appChainIds: [base.id],
  });

  const handleSignIn = async () => {
    setLoading(true);
    setError(null);

    try {
      // Get the provider and create wallet client
      const provider = sdk.getProvider();
      const client = createWalletClient({
        chain: base,
        transport: custom(provider)
      });

      // Get account address
      const [account] = await client.getAddresses();

      // Sign authentication message
      const message = `Sign in to MyApp at ${Date.now()}`;
      const signature = await client.signMessage({ 
        account,
        message,
      });

      // Verify signature on backend (optional)
      const authResult = await verifySignature(account, message, signature);

      if (authResult.success) {
        setUser({
          address: account,
          signature: signature,
          timestamp: Date.now()
        });
        console.log('User authenticated successfully');
      } else {
        throw new Error('Authentication verification failed');
      }
    } catch (err) {
      console.error('Authentication failed:', err);
      setError(err.message || 'Authentication failed');
    } finally {
      setLoading(false);
    }
  };

  const handleSignOut = () => {
    setUser(null);
    setError(null);
  };

  // Mock backend verification (replace with your API)
  const verifySignature = async (address, message, signature) => {
    // Send to your backend for verification
    const response = await fetch('/api/verify-signature', {
      method: 'POST',
      headers: { 'Content-Type': 'application/json' },
      body: JSON.stringify({ address, message, signature })
    });
    return response.json();
  };

  if (user) {
    return (
      <div className="authenticated">
        <h3>Welcome!</h3>
        <p><strong>Address:</strong> {user.address}</p>
        <p><strong>Signed in at:</strong> {new Date(user.timestamp).toLocaleString()}</p>
        <button onClick={handleSignOut} className="sign-out-btn">
          Sign Out
        </button>
      </div>
    );
  }

  return (
    <div className="authentication">
      <h2>Sign In to Continue</h2>
      <p>Connect your Base Account to access the application</p>
      
      <SignInWithBaseButton 
        align="center"
        variant="solid"
        colorScheme="light"
        size="large"
        disabled={loading}
        onClick={handleSignIn}
      />
      
      {loading && (
        <div className="loading">
          Authenticating...
        </div>
      )}
      
      {error && (
        <div className="error">
          <p>Authentication failed: {error}</p>
          <button onClick={() => setError(null)}>Try Again</button>
        </div>
      )}
      
      <style jsx>{`
        .authentication {
          max-width: 400px;
          margin: 0 auto;
          padding: 40px 20px;
          text-align: center;
        }
        
        .authenticated {
          max-width: 400px;
          margin: 0 auto;
          padding: 20px;
          background: #f8f9fa;
          border-radius: 12px;
        }
        
        .loading {
          margin-top: 20px;
          color: #666;
          font-style: italic;
        }
        
        .error {
          margin-top: 20px;
          padding: 15px;
          background: #f8d7da;
          border: 1px solid #f5c6cb;
          border-radius: 8px;
          color: #721c24;
        }
        
        .sign-out-btn {
          background: #6c757d;
          color: white;
          border: none;
          padding: 10px 20px;
          border-radius: 6px;
          cursor: pointer;
          margin-top: 15px;
        }
        
        .sign-out-btn:hover {
          background: #5a6268;
        }
      `}</style>
    </div>
  );
}

​
SIWE Integration

import { createSiweMessage } from 'siwe';

const handleSignInWithSIWE = async () => {
  try {
    const provider = sdk.getProvider();
    const client = createWalletClient({
      chain: base,
      transport: custom(provider)
    });

    const [account] = await client.getAddresses();

    // Create SIWE message
    const siweMessage = createSiweMessage({
      address: account,
      chainId: base.id,
      domain: window.location.host,
      nonce: Math.random().toString(36).substring(7),
      uri: window.location.origin,
      version: '1',
      statement: 'Sign in to MyApp with your Base Account'
    });

    // Sign the SIWE message
    const signature = await client.signMessage({ 
      account,
      message: siweMessage.prepareMessage(),
    });

    // Verify with your backend
    const authResult = await fetch('/api/siwe-verify', {
      method: 'POST',
      headers: { 'Content-Type': 'application/json' },
      body: JSON.stringify({
        message: siweMessage,
        signature: signature
      })
    });

    if (authResult.ok) {
      const userData = await authResult.json();
      setUser(userData);
    }
  } catch (error) {
    console.error('SIWE authentication failed:', error);
  }
};

<SignInWithBaseButton 
  align="center"
  variant="solid"
  colorScheme="light"
  onClick={handleSignInWithSIWE}
/>

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Custom Button States

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Loading State

function CustomSignInButton() {
  const [isLoading, setIsLoading] = useState(false);

  const handleSignIn = async () => {
    setIsLoading(true);
    try {
      // Authentication logic
      await authenticateUser();
    } finally {
      setIsLoading(false);
    }
  };

  return (
    <SignInWithBaseButton 
      disabled={isLoading}
      onClick={handleSignIn}
      colorScheme="light"
    />
  );
}

​
Error State Handling

function SignInWithErrorHandling() {
  const [error, setError] = useState(null);

  const handleSignIn = async () => {
    try {
      setError(null);
      await authenticateUser();
    } catch (err) {
      if (err.code === 4001) {
        setError('User rejected the authentication request');
      } else if (err.code === -32002) {
        setError('Authentication request already pending');
      } else {
        setError('Authentication failed. Please try again.');
      }
    }
  };

  return (
    <div>
      <SignInWithBaseButton 
        onClick={handleSignIn}
        colorScheme="light"
      />
      {error && (
        <div className="error-message">
          {error}
        </div>
      )}
    </div>
  );
}

​
Integration with Authentication Providers

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NextAuth.js Integration

// pages/api/auth/[...nextauth].js
import NextAuth from 'next-auth'
import CredentialsProvider from 'next-auth/providers/credentials'
import { verifyMessage } from 'viem'

export default NextAuth({
  providers: [
    CredentialsProvider({
      name: 'Base Account',
      credentials: {
        address: { label: 'Address', type: 'text' },
        message: { label: 'Message', type: 'text' },
        signature: { label: 'Signature', type: 'text' },
      },
      async authorize(credentials) {
        try {
          const isValid = await verifyMessage({
            address: credentials.address,
            message: credentials.message,
            signature: credentials.signature,
          });

          if (isValid) {
            return {
              id: credentials.address,
              name: credentials.address,
              email: null,
            };
          }
          return null;
        } catch (error) {
          return null;
        }
      },
    }),
  ],
});

// Frontend component
import { signIn } from 'next-auth/react';

const handleSignIn = async () => {
  // ... get signature as before
  
  const result = await signIn('credentials', {
    address: account,
    message: message,
    signature: signature,
    redirect: false,
  });

  if (result?.ok) {
    console.log('Signed in successfully');
  }
};

​
TypeScript Support

import { SignInWithBaseButton } from '@base-org/account-ui/react';

interface AuthButtonProps {
  onAuthSuccess: (userAddress: string) => void;
  onAuthError: (error: string) => void;
}

function AuthButton({ onAuthSuccess, onAuthError }: AuthButtonProps) {
  const handleSignIn = async () => {
    try {
      // Authentication logic
      const userAddress = await authenticateUser();
      onAuthSuccess(userAddress);
    } catch (error) {
      onAuthError(error.message);
    }
  };

  return (
    <SignInWithBaseButton 
      align="center"
      variant="solid"
      colorScheme="light"
      onClick={handleSignIn}
    />
  );
}

​
Best Practices

  1. Handle Loading States: Disable the button during authentication to prevent multiple attempts

  2. Error Handling: Provide clear error messages for different failure scenarios

  3. Security: Always verify signatures on your backend before trusting authentication

  4. User Experience: Show clear feedback during the authentication process

  5. Accessibility: The button includes proper ARIA labels and keyboard navigation

  6. Testing: Test with different wallet states (connected, disconnected, etc.)

The SignInWithBaseButton provides a complete, production-ready authentication solution that handles all the complexity of wallet-based authentication while providing a familiar user experience.