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# HTTP headers that make your website go faster


- **Date:** Friday, Jul 11, 2025
- **Time:** 10:20–10:50 (30 min)
- **Room:** Stage 9
- **Event:** World Congress 2025
- **Tags:** performance

## Recording

[Watch recording](https://www.wearedevelopers.com/videos/1676-http-headers-that-make-your-website-go-faster)

## Description

Achieving your web performance and scalability goals often requires the use of caching.  Did you know that HTTP comes with a set of built-in conventional caching mechanisms?

In this presentation, we'll take a closer look at these caching mechanisms, and the HTTP headers that are used to enforce the caching behavior.

We'll look at a typical "Cache-Control" header and dissect the various directives that this header offers.  Covering topics like TTL, tolerated staleness, caching scope, error handling and revalidation.

There are more headers that HTTP offers to control the behavior of the cache. Headers like "Vary" to set cache variations. Or "Etag" and "If-None-Match" to perform conditional revalidation. And also "Surrogate-Capability" and "Surrogate-Control" to perform edge compute logic and handle edge-side includes.

And while this is not a Varnish-specific presentation, I will be using Varnish as the implementation to showcase the power of HTTP's built-in caching capabilities.

## Speaker

### [Thijs Feryn](https://www.wearedevelopers.com/@thijs-feryn)

Technical Evangelist at Varnish Software


## Related talks at this congress

- [Blazing Fast Page Navigation with Speculation Rules](https://www.wearedevelopers.com/events/world-congress-2025/sessions/682-blazing-fast-page) — Medhat Dawoud
- [IP Authentication: A Tale of Performance Pitfalls and Challenges in Prod](https://www.wearedevelopers.com/events/world-congress-2025/sessions/660-ip-authentication-a) — Christoph Eicke
- [High performance Serverless Java on AWS](https://www.wearedevelopers.com/events/world-congress-2025/sessions/623-high-performance) — Vadym Kazulkin
- [Lessons learned from building a thriving Vue.js SaaS application](https://www.wearedevelopers.com/events/world-congress-2025/sessions/923-lessons-learned-from) — Abdelrahman Awad