Caching Strategies for Better Performance

What is Caching?

Caching stores copies of data so future requests are served faster — avoiding repeated expensive work like database queries or network calls.

Types of Caching

Type	Where
Browser cache	User's device
CDN cache	Edge servers
Server cache	Redis, Memcached
Database cache	Query results

Browser Caching

Cache-Control: max-age=31536000, immutable  # static assets
Cache-Control: no-cache                      # always revalidate

Server-Side with Redis

// Check cache first
let data = await redis.get("users");
if (!data) {
  data = await db.query("SELECT * FROM users");
  await redis.set("users", JSON.stringify(data), "EX", 300);
}

Cache Invalidation

"There are only two hard things: cache invalidation and naming things." Strategies:

• TTL — expire after a set time.
• On write — clear cache when data changes.
• Versioned URLs — app.v2.js.

FAQs

What should I cache?

Frequently-read, rarely-changing data — static assets, API responses. More in our Performance guides.

What is a CDN?

A network of servers that cache your content near users globally.