Learn how to secure your Spring Boot APIs using rate limiting, replay attack prevention, and HMAC signature validation. Includes production-ready code examples and filter configurations.

“Security isn’t what you add at the end — it’s what you design from the start.”

If your Spring Boot app exposes APIs — to web clients, mobile apps, or third-party systems — you’re sitting on potential vulnerabilities:

• 🚨 Replay attacks (attackers resend captured requests)
• ⚡ Current limiting failures (DoS via too many requests)
• 🔐 Signature bypasses (tampered or unsigned payloads)

This guide dives deep into how I built a production-grade interface security layer for my Spring Boot microservices — using rate limiting, nonce/timestamp-based replay prevention, and HMAC signature validation.

⚙️ Step 1: Understanding the Threats

You can’t rely on HTTPS alone — it encrypts data, not intent.
That’s why API-level…