Developer Documentation

Authentication Flow Examples

This document provides examples and best practices for implementing authentication flows in your applications. Understanding these flows is crucial for securing user data and controlling access to your services.

Basic User Authentication (Username/Password)

This is the most common and straightforward authentication method, typically used for direct user logins.

Implementation Example (Conceptual)

This is a simplified representation. Actual implementations involve secure password hashing (e.g., bcrypt) and session management.

// Client-side (e.g., using fetch API)
async function loginUser(username, password) {
    try {
        const response = await fetch('/api/login', {
            method: 'POST',
            headers: { 'Content-Type': 'application/json' },
            body: JSON.stringify({ username, password })
        });
        if (!response.ok) {
            throw new Error('Login failed');
        }
        const data = await response.json();
        localStorage.setItem('authToken', data.token); // Store token
        console.log('Login successful!');
    } catch (error) {
        console.error('Login error:', error);
    }
}

// Server-side (e.g., Node.js with Express)
app.post('/api/login', async (req, res) => {
    const { username, password } = req.body;
    const user = await findUserByUsername(username);
    if (user && await verifyPassword(password, user.hashedPassword)) {
        const token = generateAuthToken(user.id); // Create JWT or session token
        res.json({ token });
    } else {
        res.status(401).json({ message: 'Invalid credentials' });
    }
});
                

OAuth 2.0 Authorization Code Flow

Ideal for allowing users to log in to your application using third-party providers like Google, Facebook, or GitHub, without storing their credentials on your server.

Key Components

• Authorization Server: The third-party service (e.g., Google).
• Client: Your application.
• Resource Owner: The end-user.
• Authorization Code: A temporary credential exchanged for an access token.
• Access Token: Used to access protected resources on behalf of the user.

Example Flow Steps

1. Your application redirects the user to the OAuth provider's authorization URL, including your client ID and a redirect URI.
2. The user logs into the provider and grants your application permission.
3. The provider redirects the user back to your redirect URI with an authorization code.
4. Your server receives the code and makes a secure, back-channel request to the provider's token endpoint, exchanging the code for an access token and possibly a refresh token.
5. Your application uses the access token to make API calls to the provider on behalf of the user.

API Key Authentication

Suitable for server-to-server communication or when a user doesn't need to be directly involved in the authentication process. API keys act as a secret identifier.

Usage

API keys are typically sent in request headers, often as X-API-Key or Authorization: ApiKey YOUR_API_KEY.

GET /api/v1/data HTTP/1.1
Host: api.example.com
X-API-Key: YOUR_SECRET_API_KEY_HERE
                

Security Considerations

• Treat API keys like passwords. Do not embed them directly in client-side code.
• Use environment variables or secure configuration management.
• Consider rotating API keys regularly.
• Implement rate limiting to prevent abuse.