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Intermediate 20 min readModule: Module 8: Authentication with JWT & Bcrypt Hashing

JWT Authentication & Password Security

Implement secure user registration, bcrypt password hashing, and stateless JSON Web Tokens.

What You Will Learn in This Lesson

  • Why plain text passwords must never be stored
  • Salting and hashing passwords with bcrypt
  • Signing and verifying JWT access tokens

Introduction & Core Concept

JSON Web Tokens (JWT) are an open standard for securely transmitting information between parties as a JSON object.
WHY DOES THIS MATTER IN THE REAL WORLD?

Stateless JWT authentication enables horizontal scaling across dozens of distributed server containers.

User Sign-In & JWT Generation

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const jwt = require("jsonwebtoken");
const bcrypt = require("bcryptjs");
 
async function handleLogin(email, password, userRecord) {
  const isMatch = await bcrypt.compare(password, userRecord.hashedPassword);
  if (!isMatch) throw new Error("Invalid credentials");
  const token = jwt.sign({ userId: userRecord.id }, process.env.JWT_SECRET, { expiresIn: "2h" });
  return { token };
}

Line-by-Line Technical Breakdown

1Tokens are sent in the Authorization header: Bearer <token>.

Try It Yourself (Interactive Editor)

Modify the code in real-time and click Run to test live browser output and console logs.

Intelligent Code Runner & Live Sandbox[JAVASCRIPT]
JAVASCRIPT SOURCE EDITOR
Interactive Live Code

Industry Best Practices & Professional Standards

  • Always store JWT secret keys in environment variables (.env).

Lesson Summary & Core Takeaways

  • JWT tokens provide secure, stateless identity verification.