Quickly experiment, debug and try out ideas on Fastly's platform, without signing up, or even logging in.

Keeping your digital presence continuously tuned, optimized, and secure to align with changing business and technical requirements can be time consuming. That’s why we’ve put together our…

Websites still load too slowly. During the most critical time in the page load lifecycle, your connection is often almost totally idle. At Fastly, we’re watching a new technology that…

Learn how to clear a cache memory with JavaScript to fix errors and improve front end performance.

Without realizing it, many of us are building single points of failure into our stack. Fastly customer ButterCMS requires near-100% uptime for their customers, but after multiple outages…

Browsers need to understand and respond to Vary rules, and the way they do this is different from the way Vary is treated by CDNs. In this post, Principal Developer Advocate Andrew Betts…

Requesting the difference between two previously cached files — using just a CDN configuration and a serverless cloud compute function — is a great example of exploiting edge and serverless…

Fastly’s engineering teams are smart and capable — they architect thoughtfully, write elegant code, and work carefully with incredible complexity and scale. So why would they (or anyone…

We’ve worked to ensure the Fastly Image Optimizer is simple, easy to use, and most importantly fully integrated into the platform. In an effort to give you even more control, we've developed…

Server-sent events allow web servers to push real-time event notifications to the browser on a long-lived HTTP response. It's a beautiful part of the web platform that’s severely underused…

You can use the Vary response header in creative ways, including A/B testing and internationalization. At the same time, many people still use Vary badly or misunderstand what it does; in…

Surrogate keys give Fastly customers a unique way to efficiently purge content from cache — batch API for surrogate key purge allows you to purge content even more efficiently by purging…