This One Spring Boot Change Made My API 10 Faster (It Wasn’t Caching)

Response time dropped from 1200ms → 120ms. I always thought caching was the biggest performance booster… Turns out, I was completely overlooking something much simpler. After reducing my API response size by 80%, the performance improvement was insane — nearly 10× faster responses. In this article, I break down: Why large payloads silently kill performance The exact mistake I was making in Spring Boot How I fixed it with a simple change Real before vs after impact If you're working with