📧 AutoMailer – Email OTP & Transactional Email Service

A Spring Boot application that currently allows sending OTP emails for verification.
It can be used to verify user email addresses during signup, password reset, or other secure actions. 🔐

In the future, it may expand to support general email sending and transactional notifications.

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🚀 Features

• 📩 Send OTPs via email for verification
• ✅ Verify OTPs with expiration time
• 🛠 Configurable SMTP settings
• 🗂 Clean architecture with logs for debugging
• 🔒 Secure handling of OTP storage (in-memory / database support)

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🧱 Tech Stack

• ☕ Java 21, Spring Boot 3.5.5
• 📬 Jakarta Mail via JavaMailSender
• 🧰 Lombok (@Slf4j, @RequiredArgsConstructor)
• 🐳 Docker / Docker Compose
• 🦾 Distroless base image → minimal, secure runtime (no shell, no package manager)
• 👨‍💻 Rootless container execution → runs as non-root user for extra security

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📡 API Endpoints

1️⃣ Send OTP

POST /generateOTP Request Body:

{
  "email": "user@example.com"
}

Response: "OTP sent successfully!"

2️⃣ Verify OTP

POST /verify Request Body:

{
  "email": "user@example.com",
  "otp": "123456"
}

Response (if valid): "OTP verified successfully!"

Response (if invalid/expired): "Invalid or expired OTP!"

3️⃣ Send Welcome Email

POST /sendWelcomeEmail Request Body:

{
    "email": "user@example.com",
    "name": "User Name"
}

Response: "Welcome email sent successfully!"

4️⃣ Send Password Reset Email

POST /reset-password

Request Body:

{
    "email": "user@example.com",
    "resetToken": "1234567890abcdef",
    "resetLink": "https://example.com/reset-password?token=1234567890abcdef",
    "name": "User Name"
}

Response: "Password reset email sent successfully!"

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🛡 Security Notes

• Store secrets like SMTP password in .env (not in application.properties).
• If using docker-compose, mount .env instead of hardcoding secrets.
• Never commit .env or application.properties with real credentials to GitHub.

🚀 Roadmap / Future Plans

• ✅ Send OTP emails for verification
• 📩 Support transactional emails (welcome mail, password reset, etc.)
• 📑 Email templates with HTML + branding
• 🔑 Pluggable OTP strategies (numeric, alphanumeric, time-based)
• 📊 Admin dashboard for email delivery stats & OTP success rate
• 🌐 Multi-channel OTP (Email + SMS + WhatsApp)
• ☁️ Cloud-native deployment (Kubernetes, Helm charts)
• 🛡️ Secret manager integration (Vault, AWS Secrets Manager, GCP Secret Manager)