Learning Path
Improve HTTP Performance and Caching
A practical path for faster responses, safer caching, and better client-server efficiency.
Built for: Engineers working on API latency, browser performance, CDN behavior, and cache correctness.
What you should get from this path
- Choose sane Cache-Control policies.
- Understand validators, freshness, and conditional requests.
- Spot performance headers that matter for browsers and caches.
Read the performance guides
These pages provide the higher-level model for cache behavior and protocol performance.
HTTP Headers and Caching: A Practical Guide
Master HTTP caching with Cache-Control, ETag, Last-Modified, and conditional request headers. Learn how to optimize performance with proper cache strategies.
Explains how headers combine to control browser and intermediary behavior.
HTTPS and TLS: How Secure Connections Work
Beginner-to-advanced guide to HTTP vs HTTPS, TLS basics, migration checklists, and HTTP/1.1 vs HTTP/2 tradeoffs for production systems.
Covers the transport overhead and security foundation underneath HTTP performance.
Know the headers that matter
Use these references to move from general theory to exact directives.
Cache-Control Header: Complete HTTP Caching Guide
Master the Cache-Control header. Learn how to control browser and CDN caching with max-age, no-cache, no-store, and other directives.
Primary control surface for freshness, revalidation, and cacheability.
ETag
Learn how the ETag header provides a unique identifier for resource versions, enabling efficient cache validation and conditional requests to reduce bandwidth.
Needed for conditional requests and avoiding unnecessary payload transfers.
Last-Modified
Learn how the Last-Modified header indicates when a resource was last changed. Enable efficient cache validation with If-Modified-Since conditional requests.
A simpler validator that still matters for many browser and CDN flows.
Vary
Learn how the Vary header specifies which request headers affect the response. Essential for proper cache differentiation and content negotiation.
Essential when cache behavior differs by language, encoding, or other request traits.
Server-Timing Header
Learn how the Server-Timing header communicates server-side performance metrics to browsers. Analyze backend timing, database queries, and optimize performance.
Useful for exposing backend timing data during performance analysis.
Use tools and comparisons
These help turn policy decisions into concrete checks and tradeoff analysis.
Cache-Control Builder
Compose caching directives and get plain-English explanations instantly.
Quickly sanity-check combinations like public/private, max-age, and stale directives.
Header Inspector
Inspect real-world responses for cache headers and related response metadata.
Lets you confirm that intended policy matches actual server output.
304 Not Modified vs 200 OK
Compare cache revalidation responses against full successful responses.
Explains the practical difference between revalidation and a full successful response.
HTTP/1.1 vs HTTP/2
Understand the protocol and performance tradeoffs between HTTP versions.
Useful when performance questions extend beyond caching into connection behavior.
More Learning Paths
Debug HTTP Problems in Production
A pragmatic troubleshooting stack for the failures engineers see most often.
Learn HTTP Fundamentals
A structured route through the core primitives, message flow, and debugging basics.
Ship Secure Auth and Cookies
A security-focused path for login state, browser credentials, and defensive HTTP defaults.