Authik 🔐

A simple, zero-dependency OTP authentication module that uses Fast2SMS API to send and verify OTPs.

🚀 Installation

npm install authik

✨ Usage

const { sendOTP, verifyOTP } = require("authik");

const phone = "+91XXXXXXXXXX";
const apiKey = "YOUR_PUBLIC_FAST2SMS_API_KEY"; // keep public if for demo

// Send OTP
sendOTP(phone, apiKey).then(console.log);

// Verify OTP
const result = verifyOTP(phone, "123456");
console.log(result);

Note: This uses an in-memory store (non-persistent). Don't use for production as-is. For production, use Redis or a DB-backed store.

📦 Features

• Generate 6-digit OTPs
• Send SMS via Fast2SMS
• Verify OTPs with expiry logic
• Works with Express or standalone

🔑 API Key Usage

If this is for open demos or dev playgrounds, you can use a public test key in your examples. But don't hardcode it inside the library — keep it as a parameter like this:

sendOTP(phone, "your-public-api-key")

📖 API Reference

sendOTP(phone: string, apiKey: string): Promise<object>

Sends an OTP to the specified phone number using Fast2SMS.

Parameters:

• phone (string): Phone number with country code (e.g., "+911234567890")
• apiKey (string): Your Fast2SMS API key

Returns: Promise that resolves to the SMS API response

verifyOTP(phone: string, otp: string): object

Verifies the OTP for the given phone number.

Parameters:

• phone (string): Phone number used during OTP generation
• otp (string): The OTP entered by the user

Returns: Object with success (boolean) and message (string)

🧠 Complete Example

const { sendOTP, verifyOTP } = require("authik");

const phone = "+911234567890";
const apiKey = "your-fast2sms-api-key";

async function handleOTPFlow() {
    try {
        // Send OTP
        const response = await sendOTP(phone, apiKey);
        console.log("OTP sent:", response);
        
        // Later, when user enters OTP
        const userEnteredOTP = "123456"; // from user input
        const result = verifyOTP(phone, userEnteredOTP);
        
        if (result.success) {
            console.log("✅ OTP verified successfully!");
            // Proceed with authentication
        } else {
            console.log("❌ OTP verification failed:", result.message);
        }
    } catch (error) {
        console.error("Error:", error);
    }
}

handleOTPFlow();

⚡ Express.js Integration

const express = require("express");
const { sendOTP, verifyOTP } = require("authik");

const app = express();
app.use(express.json());

const API_KEY = "your-fast2sms-api-key";

app.post("/send-otp", async (req, res) => {
    const { phone } = req.body;
    try {
        const result = await sendOTP(phone, API_KEY);
        res.json({ success: true, data: result });
    } catch (error) {
        res.status(500).json({ success: false, error: error.message });
    }
});

app.post("/verify-otp", (req, res) => {
    const { phone, otp } = req.body;
    const result = verifyOTP(phone, otp);
    res.json(result);
});

app.listen(3000, () => {
    console.log("Server running on port 3000");
});

🛡️ Security Notes

• In-memory storage: OTPs are stored in memory and will be lost on server restart
• Production usage: For production apps, integrate with Redis or a database
• Rate limiting: Implement rate limiting to prevent OTP abuse
• API key security: Keep your Fast2SMS API key secure and use environment variables
• One-time use: OTPs are automatically deleted after verification or expiry

🔧 Configuration

Default OTP settings:

• Length: 6 digits
• Expiry: 5 minutes
• Storage: In-memory (non-persistent)

📄 License

MIT © 2025 Om Bhayde

✨ Contributing

Pull requests, ideas, and suggestions are welcome! Feel free to open an issue or contribute to the project.

💬 Support

If you use Authik in your project, let me know — I'd love to feature it!

🪄 Pro Tips

• Use environment variables for API keys: process.env.FAST2SMS_API_KEY
• Implement proper error handling for SMS delivery failures
• Add logging for security monitoring and debugging
• Consider implementing OTP retry mechanisms with exponential backoff