Java Authentication Service

A production-style Spring Boot authentication service built with JWT, email verification, password reset, and refresh token support. This project demonstrates how to build a secure and reusable authentication backend that can be integrated into any web or mobile application.

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Tech Stack

• Java 21
• Spring Boot
• Spring Security
• JWT (JSON Web Token)
• PostgreSQL (Neon)
• Brevo SMTP (Email Service)
• Maven
• Docker

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Live API Documentation

Explore and test the API using Swagger UI:

👉 Swagger UI

Swagger provides interactive API documentation where you can:

• Test authentication endpoints
• View request/response schemas
• Understand API flows

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Features

Authentication

• User registration with email & password
• Secure login with JWT authentication
• Refresh token support
• Logout with refresh token revocation

Email System

• Email verification after registration
• Password reset via email
• Email delivery using Brevo SMTP

Security

• BCrypt password hashing
• JWT authentication filter
• Stateless authentication
• Token expiration handling

Database

• PostgreSQL database
• JPA / Hibernate ORM
• Token lifecycle management

Tokens Implemented

• Access Token (JWT)
• Refresh Token
• Email Verification Token
• Password Reset Token

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API Endpoints

Authentication

Method	Endpoint	Description
POST	/api/auth/register	Register a new user
POST	/api/auth/login	Login user
POST	/api/auth/refresh	Refresh access token
POST	/api/auth/logout	Logout user

Email Verification

Method	Endpoint	Description
POST	/api/auth/verify-email	Verify email using token
GET	/api/auth/verify-email	Verify email via link

Password Reset

Method	Endpoint	Description
POST	/api/auth/forgot-password	Send password reset email
POST	/api/auth/reset-password	Reset password

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Email Flow

Email Verification

1. User registers
2. Verification token is generated
3. Email sent via Brevo
4. User clicks verification link
5. Email is marked as verified

Password Reset

1. User requests password reset
2. Reset token generated
3. Email sent with reset link
4. User sets new password

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Run Locally

Run with Maven

./mvnw spring-boot:run

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Run with Docker

Build the image:

docker build -t auth-service .

Run the container:

docker run --env-file .env -p 8080:8080 auth-service

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Test API

Health check endpoint:

GET http://localhost:8080/test

Expected response:

Rockrangerz Spring Boot Docker Test Successful

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Project Structure

authentication-service
│
├── Dockerfile
├── pom.xml
├── README.md
├── .dockerignore
├── .gitignore
├── .env.example
├── mvnw
├── mvnw.cmd
│
├── src
│   ├── main
│   │   ├── java
│   │   │   └── com
│   │   │       └── rockrager
│   │   │           └── authentication
│   │   │               │
│   │   │               ├── AuthenticationApplication.java
│   │   │               │
│   │   │               ├── config
│   │   │               │   └── SecurityConfig.java
│   │   │               │
│   │   │               ├── controller
│   │   │               │   ├── AuthController.java
│   │   │               │   └── TestController.java
│   │   │               │
│   │   │               ├── dto
│   │   │               │   ├── request
│   │   │               │   │   ├── RegisterRequest.java
│   │   │               │   │   ├── LoginRequest.java
│   │   │               │   │   ├── RefreshTokenRequest.java
│   │   │               │   │   ├── LogoutRequest.java
│   │   │               │   │   ├── VerifyEmailRequest.java
│   │   │               │   │   ├── ForgotPasswordRequest.java
│   │   │               │   │   └── ResetPasswordRequest.java
│   │   │               │   │
│   │   │               │   └── response
│   │   │               │       └── AuthResponse.java
│   │   │               │
│   │   │               ├── entity
│   │   │               │   ├── User.java
│   │   │               │   ├── RefreshToken.java
│   │   │               │   ├── EmailVerificationToken.java
│   │   │               │   └── PasswordResetToken.java
│   │   │               │
│   │   │               ├── repository
│   │   │               │   ├── UserRepository.java
│   │   │               │   ├── RefreshTokenRepository.java
│   │   │               │   ├── EmailVerificationTokenRepository.java
│   │   │               │   └── PasswordResetTokenRepository.java
│   │   │               │
│   │   │               ├── security
│   │   │               │   ├── jwt
│   │   │               │   │   ├── JwtAuthenticationFilter.java
│   │   │               │   │   └── JwtService.java
│   │   │               │   │
│   │   │               │   └── user
│   │   │               │       ├── CustomUserDetails.java
│   │   │               │       └── CustomUserDetailsService.java
│   │   │               │
│   │   │               ├── service
│   │   │               │   ├── AuthService.java
│   │   │               │   └── EmailService.java
│   │   │               │
│   │   │               └── util
│   │   │
│   │   └── resources
│   │       ├── application.properties
│   │       ├── static
│   │       └── templates
│   │
│   └── test
│       └── java
│           └── com
│               └── rockrager
│                   └── authentication
│                       └── AuthenticationApplicationTests.java

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Database Tables

• users
• refresh_tokens
• email_verification_tokens
• password_reset_tokens

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Future Improvements

• HTML email templates
• OAuth login (Google / GitHub)
• API rate limiting
• Swagger API documentation
• Deployment to cloud platforms

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Author

Mohan Kumar

Backend Developer | Java | Spring Boot