5 Proven API Performance Hacks for High‑Concurrency Systems

1️⃣ Pagination Optimization

Scenario: querying millions of records. Techniques: use cursor pagination instead of OFFSET, default 20 items per page, toggle totalCount.

2️⃣ Asynchronous Logging

Replace synchronous disk writes with buffering logs in memory and batch flushing, achieving a 3‑5× performance boost.

3️⃣ Multi‑Level Caching

First layer: local cache (Guava/Caffeine). Second layer: distributed cache (Redis). Key configurations: set appropriate TTL and protect against cache penetration.

4️⃣ Data Compression

Compress requests with gzip/deflate, enable HTTP/2, use MessagePack for large JSON, reducing payload size by over 60%.

5️⃣ Connection Pool Tuning

Key parameters: maxWaitMillis for timeout control, maxActive for maximum connections. Monitor active connections and waiting threads.

Golden rule: monitor before optimizing; APM tools are essential.