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Authentication Tutorials

Authentication is how applications verify who a user is and protect their accounts. This complete course covers passwords and hashing, sessions and cookies, JWTs, OAuth 2.0, OpenID Connect, social login, SSO, multi-factor authentication, passkeys and WebAuthn, authorization, and security best practices.

What Is Authentication?

Authentication is the process of verifying that users are who they claim to be, while authorization decides what they are allowed to do. Together they protect accounts and data using credentials, tokens, sessions, and additional factors.

Why Learn Authentication?

Almost every application needs secure login, and authentication mistakes are among the most damaging security bugs. Learning authentication properly lets you protect users, meet compliance requirements, and integrate identity providers with confidence.

What You Will Learn

This course is organized into focused lessons so you can learn step by step. You will start with identity fundamentals, registration, and passwords, then move through sessions and cookies, JWTs, OAuth 2.0 and OpenID Connect, social login and SSO, multi-factor and passwordless authentication, authorization models, framework integrations, and security hardening.

Complete Authentication Roadmap

Follow this structured Authentication roadmap to learn every important topic with examples, cheatsheets, and practical usage guidance.

01

Authentication Basics

Authentication Article Series • 5 lessons

Covers Authentication - Introduction, Authentication - Basics, and 3 more lessons.

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02

Identity Fundamentals

Authentication Article Series • 5 lessons

Covers Digital Identity, Users, Identities, and Accounts, and 3 more lessons.

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03

Authentication vs Authorization

Authentication Article Series • 5 lessons

Covers Authentication vs Authorization, Identification vs Authentication, and 3 more lessons.

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04

Authentication Factors

Authentication Article Series • 5 lessons

Covers Authentication Factors, Knowledge Factors, and 3 more lessons.

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05

Registration

Authentication Article Series • 5 lessons

Covers User Registration, Build a Signup Form, and 3 more lessons.

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06

Login

Authentication Article Series • 5 lessons

Covers User Login, Build a Login Form, and 3 more lessons.

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07

Password Authentication

Authentication Article Series • 5 lessons

Covers Password Authentication, Secure Password Storage, and 3 more lessons.

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08

Password Hashing

Authentication Article Series • 5 lessons

Covers bcrypt, Argon2, and 3 more lessons.

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09

Password Policies

Authentication Article Series • 5 lessons

Covers Password Policies, Password Strength, and 3 more lessons.

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10

Password Reset

Authentication Article Series • 5 lessons

Covers Password Reset, Forgot Password Flow, and 3 more lessons.

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11

Email Verification

Authentication Article Series • 5 lessons

Covers Email Verification, Email Verification Tokens, and 3 more lessons.

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12

Phone Verification

Authentication Article Series • 5 lessons

Covers Phone Verification, SMS One-Time Passwords, and 3 more lessons.

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13

Session Authentication

Authentication Article Series • 5 lessons

Covers Session Authentication, Server-Side Sessions, and 3 more lessons.

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14

Cookies

Authentication Article Series • 5 lessons

Covers Authentication Cookies, HttpOnly Cookies, and 3 more lessons.

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15

Session Security

Authentication Article Series • 5 lessons

Covers Session Security, Session Fixation, and 3 more lessons.

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16

JSON Web Tokens

Authentication Article Series • 5 lessons

Covers JSON Web Tokens, JWT Structure, and 3 more lessons.

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17

JWT Claims

Authentication Article Series • 5 lessons

Covers JWT Claims, Registered Claims, and 3 more lessons.

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18

JWT Signing

Authentication Article Series • 5 lessons

Covers JWT Signing, Symmetric JWT Signing, and 3 more lessons.

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19

Access and Refresh Tokens

Authentication Article Series • 5 lessons

Covers Access Tokens, Refresh Tokens, and 3 more lessons.

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20

Token Storage

Authentication Article Series • 5 lessons

Covers Authentication Token Storage, Tokens in Local Storage, and 3 more lessons.

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21

Bearer Authentication

Authentication Article Series • 5 lessons

Covers Bearer Authentication, Authorization Header, and 3 more lessons.

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22

API Keys

Authentication Article Series • 5 lessons

Covers API Key Authentication, Generate API Keys, and 3 more lessons.

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23

Basic Authentication

Authentication Article Series • 5 lessons

Covers HTTP Basic Authentication, Basic Authorization Header, and 3 more lessons.

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24

OAuth 2.0

Authentication Article Series • 5 lessons

Covers OAuth 2.0, OAuth Roles, and 3 more lessons.

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25

OAuth Authorization Code

Authentication Article Series • 5 lessons

Covers Authorization Code Flow, Authorization Request, and 3 more lessons.

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26

PKCE

Authentication Article Series • 5 lessons

Covers Proof Key for Code Exchange, PKCE Code Verifier, and 3 more lessons.

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27

OAuth Client Credentials

Authentication Article Series • 5 lessons

Covers Client Credentials Flow, Machine-to-Machine Authentication, and 3 more lessons.

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28

OAuth Device Flow

Authentication Article Series • 5 lessons

Covers Device Authorization Flow, Device Code, and 3 more lessons.

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29

OpenID Connect

Authentication Article Series • 5 lessons

Covers OpenID Connect, OpenID Connect vs OAuth, and 3 more lessons.

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30

OIDC Discovery

Authentication Article Series • 5 lessons

Covers OpenID Connect Discovery, Well-Known Configuration, and 3 more lessons.

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31

Social Login

Authentication Article Series • 5 lessons

Covers Social Login, Google Login, and 3 more lessons.

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32

Single Sign-On

Authentication Article Series • 5 lessons

Covers Single Sign-On, How SSO Works, and 3 more lessons.

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33

SAML

Authentication Article Series • 5 lessons

Covers SAML Authentication, SAML Assertions, and 3 more lessons.

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34

Enterprise Authentication

Authentication Article Series • 5 lessons

Covers Enterprise Authentication, Active Directory Authentication, and 3 more lessons.

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35

Multi-Factor Authentication

Authentication Article Series • 5 lessons

Covers Multi-Factor Authentication, Two-Factor Authentication, and 3 more lessons.

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36

Authenticator Apps

Authentication Article Series • 5 lessons

Covers Authenticator Apps, Time-Based One-Time Passwords, and 3 more lessons.

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37

Recovery Codes

Authentication Article Series • 5 lessons

Covers Recovery Codes, Generate Recovery Codes, and 3 more lessons.

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38

Passwordless Authentication

Authentication Article Series • 5 lessons

Covers Passwordless Authentication, Email Magic Links, and 3 more lessons.

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39

WebAuthn

Authentication Article Series • 5 lessons

Covers WebAuthn, WebAuthn Registration, and 3 more lessons.

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40

Passkeys

Authentication Article Series • 5 lessons

Covers Passkeys, Passkey Registration, and 3 more lessons.

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41

Biometric Authentication

Authentication Article Series • 5 lessons

Covers Biometric Authentication, Fingerprint Authentication, and 3 more lessons.

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42

Adaptive Authentication

Authentication Article Series • 5 lessons

Covers Adaptive Authentication, Risk-Based Authentication, and 3 more lessons.

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43

Authorization Models

Authentication Article Series • 5 lessons

Covers Authorization Models, Role-Based Access Control, and 3 more lessons.

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44

Roles and Permissions

Authentication Article Series • 5 lessons

Covers Roles and Permissions, Role Design, and 3 more lessons.

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45

Frontend Authentication

Authentication Article Series • 5 lessons

Covers Frontend Authentication, Manage Login State, and 3 more lessons.

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46

React Authentication

Authentication Article Series • 5 lessons

Covers Authentication with React, React Auth Provider, and 3 more lessons.

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47

Next.js Authentication

Authentication Article Series • 5 lessons

Covers Authentication with Next.js, Next.js App Router Authentication, and 3 more lessons.

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48

Node.js Authentication

Authentication Article Series • 5 lessons

Covers Authentication with Node.js, Node.js User Registration, and 3 more lessons.

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49

Express Authentication

Authentication Article Series • 5 lessons

Covers Authentication with Express, Express Authentication Middleware, and 3 more lessons.

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50

NestJS Authentication

Authentication Article Series • 5 lessons

Covers Authentication with NestJS, NestJS Authentication Guards, and 3 more lessons.

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51

GraphQL Authentication

Authentication Article Series • 5 lessons

Covers GraphQL Authentication, GraphQL Authentication Context, and 3 more lessons.

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52

REST API Authentication

Authentication Article Series • 5 lessons

Covers REST API Authentication, JWT for REST APIs, and 3 more lessons.

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53

Microservices Authentication

Authentication Article Series • 5 lessons

Covers Microservices Authentication, Service-to-Service Authentication, and 3 more lessons.

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54

Cloud Authentication

Authentication Article Series • 5 lessons

Covers Cloud Authentication, AWS Authentication, and 3 more lessons.

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55

Identity Providers

Authentication Article Series • 5 lessons

Covers Identity Providers, Authentication with Auth0, and 3 more lessons.

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56

Firebase Authentication

Authentication Article Series • 5 lessons

Covers Firebase Authentication, Firebase Email and Password, and 3 more lessons.

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57

Database Design

Authentication Article Series • 5 lessons

Covers Authentication Database Design, Users Table Design, and 3 more lessons.

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58

Account Management

Authentication Article Series • 5 lessons

Covers Account Management, Update User Profile, and 3 more lessons.

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59

Account Linking

Authentication Article Series • 5 lessons

Covers Account Linking, Link Social Accounts, and 3 more lessons.

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60

Device and Session Management

Authentication Article Series • 5 lessons

Covers Device and Session Management, View Active Sessions, and 3 more lessons.

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61

Brute-Force Protection

Authentication Article Series • 5 lessons

Covers Brute-Force Protection, Login Rate Limiting, and 3 more lessons.

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62

Common Attacks

Authentication Article Series • 5 lessons

Covers Common Authentication Attacks, Credential Stuffing, and 3 more lessons.

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63

Web Security

Authentication Article Series • 5 lessons

Covers Authentication Web Security, Cross-Site Request Forgery, and 3 more lessons.

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64

Token Security

Authentication Article Series • 5 lessons

Covers Token Security, Token Theft, and 3 more lessons.

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65

Secrets and Key Management

Authentication Article Series • 5 lessons

Covers Authentication Secrets Management, Environment Variables, and 3 more lessons.

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66

Audit and Compliance

Authentication Article Series • 5 lessons

Covers Authentication Audit and Compliance, Authentication Logs, and 3 more lessons.

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67

Logging and Monitoring

Authentication Article Series • 5 lessons

Covers Authentication Logging and Monitoring, Login Event Logging, and 3 more lessons.

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68

Error Handling

Authentication Article Series • 5 lessons

Covers Authentication Error Handling, Invalid Credentials, and 3 more lessons.

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69

Authentication UX

Authentication Article Series • 5 lessons

Covers Authentication User Experience, Login Form Usability, and 3 more lessons.

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70

Authentication Accessibility

Authentication Article Series • 5 lessons

Covers Authentication Accessibility, Accessible Login Forms, and 3 more lessons.

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71

Testing

Authentication Article Series • 5 lessons

Covers Authentication Testing, Authentication Unit Testing, and 3 more lessons.

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72

Mocking Authentication

Authentication Article Series • 5 lessons

Covers Mock Authentication, Mock Authenticated Users, and 3 more lessons.

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73

Performance

Authentication Article Series • 5 lessons

Covers Authentication Performance, Session Store Performance, and 3 more lessons.

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74

High Availability

Authentication Article Series • 5 lessons

Covers Highly Available Authentication, Distributed Sessions, and 3 more lessons.

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75

Deployment

Authentication Article Series • 5 lessons

Covers Deploy Authentication Systems, Environment Configuration, and 3 more lessons.

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76

CI/CD

Authentication Article Series • 5 lessons

Covers Authentication CI/CD, Secure Secret Injection, and 3 more lessons.

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77

Architecture

Authentication Article Series • 5 lessons

Covers Authentication Architecture, Centralized Authentication, and 3 more lessons.

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78

Zero Trust

Authentication Article Series • 5 lessons

Covers Zero Trust Authentication, Continuous Verification, and 3 more lessons.

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79

Advanced

Authentication Article Series • 5 lessons

Covers Advanced Authentication, OAuth Token Exchange, and 3 more lessons.

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80

Projects

Authentication Article Series • 5 lessons

Covers Session-Based Login System, JWT-Protected REST API, and 3 more lessons.

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81

Troubleshooting

Authentication Article Series • 5 lessons

Covers Authentication Troubleshooting, Login Not Working, and 3 more lessons.

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82

Reference

Authentication Article Series • 5 lessons

Covers Authentication Best Practices, Authentication Do's and Don'ts, and 3 more lessons.

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83

Interview

Authentication Article Series • 5 lessons

Covers Authentication Interview Questions, Authentication System Design Questions, and 3 more lessons.

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Who Is This Authentication Tutorial For?

This tutorial is useful for frontend, backend, and full-stack developers, security engineers, and interview candidates who want clear explanations of authentication paired with practical, real-world examples.

Start Learning Authentication

Begin with the introduction lesson and continue through the sidebar in order. Each lesson explains one concept clearly and shows how to apply it confidently in real, secure applications.