Introduction: Why Cacheability Matters
Caching can turn a sluggish API into a lightning-fast experience. By storing responses closer to the client, you cut down on server load and latency. But there’s a catch: more caching can mean less fresh data.
The art is finding the sweet spot between performance and consistency.
The Promise and the Risk
Promise: Faster responses, reduced infrastructure costs, better user experience.
Risk: Serving stale or incorrect data that can frustrate users — or worse, cause business errors.
The best engineers treat caching as a strategic tool, not an afterthought.
When to Use Cacheable Responses
High-read, low-change data
If your data changes once a day but is read thousands of times an hour, cache it aggressively.
Public APIs with predictable patterns
Endpoints like /currencies or /weather/today can benefit from CDN caching.
APIs under heavy traffic
Caching absorbs request spikes before they hit your origin servers.
When to Avoid Cacheable Responses
Frequently changing data
Stock prices, auction bids, or sports scores change too often for meaningful caching.
Real-time or transactional systems
Payment gateways or booking systems can’t risk out-of-date states.
Personal or sensitive data
User profiles or medical records should avoid public cache layers.
Types of Caching
CDN and edge caching
Content Delivery Networks store responses at global edge locations. Great for public static or semi-static data.
Application-level caching
Caching at the backend layer, such as Redis or Memcached, for faster recomputation.
Client-side caching
Use HTTP headers like Cache-Control and Expires to let browsers store results locally.
Choosing Cache Duration
Short TTL for fast-changing data
A few seconds to a minute keeps results fresh while still easing load.
Long TTL for rarely updated data
If your countries list changes yearly, you can safely set TTL in days.
Stale-while-revalidate patterns
Serve cached content instantly, then refresh it in the background for next time.
Balancing Performance and Consistency
Understand your domain’s tolerance for staleness
In ecommerce search results, a few minutes stale is often fine; in financial trading, it’s not.
Monitor cache hit/miss ratios
If your hit rate is low, you may be expiring too soon.
Apply conditional requests
Use ETag or Last-Modified with If-None-Match headers to minimize over-fetching.
Practical Example with JuheAPI
JuheAPI, at juheapi.com with its Hub at https://hub.juheapi.com/, exposes endpoints where caching can shine.
For example, an endpoint like /exchangerate/v2/getcode (hypothetical) could be cached at the CDN for 24 hours.
Suggested strategies:
- Public data like weather, holidays, or exchange rates: External CDN cache with TTL from 10 minutes to 1 hour.
- Semi-real-time data like traffic info: Short TTL (30–60 seconds) with stale-while-revalidate.
- Private data: Cache in secured server memory if at all, avoid public caches.
Checklist for Deciding Cacheability
- Is the data public?
- How often does it change?
- Can consumers tolerate stale content for X seconds/minutes?
- What’s the traffic pattern?
- Do we already have headers like
ETagorCache-Controlset? - Do we have monitoring for cache performance?
Conclusion: Make Caching a Strategic Tool
Cacheable responses aren’t about blindly turning on Cache-Control. They’re about making intentional tradeoffs that suit your domain, your traffic, and your users.
Master the balance, and caching becomes not just a performance booster, but a resilience multiplier.