Java Companion

Feb 21, 2026 · Backend Development

Build Your Own Spring Boot API Guard: Anti‑Duplicate Submissions and Rate Limiting

The article introduces Guardian, a lightweight Spring Boot starter that provides independent anti‑duplicate‑submission and rate‑limiting modules, explains why a custom solution is preferable to raw Redis locks, and walks through annotation and YAML configurations, key generation, response handling, storage options, concurrency safety, and observability.