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Passwordless Authentication Patterns — Implementing Passwordless Auth in Production

DodaTech Updated 2026-06-28 1 min read

In this tutorial, you'll learn about Passwordless Authentication. We cover key concepts, practical examples, and best practices to help you understand and apply this topic effectively.

Passwordless authentication eliminates password-related vulnerabilities while improving user experience through magic links, OTP codes, and biometric authentication.

// Magic link implementation
async function sendMagicLink(email) {
  const token = crypto.randomBytes(32).toString('hex');
  const expires = Date.now() + 15 * 60 * 1000;

  await redis.set(`magic_link:${token}`, email, 'PX', 15 * 60 * 1000);

  await emailService.send({
    to: email,
    subject: 'Sign in to ScanApp',
    body: `Click to sign in: https://scanapp.com/auth/magic-link?token=${token}`
  });
}

app.get('/auth/magic-link', async (req, res) => {
  const { token } = req.query;
  const email = await redis.get(`magic_link:${token}`);

  if (!email) return res.status(401).json({ error: 'Invalid or expired link' });

  await redis.del(`magic_link:${token}`);
  const jwt = generateJwt({ email });
  res.json({ token: jwt });
});

// OTP delivery
async function sendOtp(phone) {
  const code = Math.floor(100000 + Math.random() * 900000).toString();
  await redis.set(`otp:${phone}`, code, 'PX', 5 * 60 * 1000);
  await smsService.send(phone, `Your ScanApp code is: ${code}`);
}

Passwordless auth improves security by eliminating password reuse, phishing via passwords, and credential stuffing attacks.

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