Caching is a way to make frequently requested data available without repeating expensive work. In a Spring Boot service, Redis is often a good shared cache because it is fast and works across multiple application instances.
Start with the data path
Before adding a cache, identify the request path and the expensive operation inside it. This is usually a database query, an external API request, or computation that does not change for every request.
@Cacheable(cacheNames = "products", key = "#id")
public Product findProduct(String id) {
return productRepository.findById(id)
.orElseThrow(() -> new ProductNotFoundException(id));
}Choose a useful cache lifetime
Cache invalidation should follow the data’s freshness needs. A short time-to-live is usually a safer first choice than a cache that never expires.
Treat a cache as an optimization layer, not the system of record.
What to measure
Track cache hits, misses, latency, and Redis errors. These measurements make it clear whether the cache improves the user experience or simply adds operational complexity.