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…

Since we made HTTP/2 generally available in November 2016, h2 traffic has been steadily growing as more customers migrate to the new version of the protocol; since the beginning of 2017, h…

Since a CDN is essentially a cache, you might be tempted to avoid complexity by not making use of the browser cache. However, each cache has its own advantages that the other does not…

One of the most common metrics for evaluating CDN performance is cache hit ratio (CHR). CDN customers have used it for years as a primary indicator of how well a CDN is serving their users…

Our CDN can cache more content than traditional solutions (static as well as rapidly changing, “event-driven” content), offloading traffic that would otherwise go to origin, allowing our…