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Fastly Blog

Performance

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Introducing Quick Value Packages

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 Quick Value Packages — a collection of expert…

Towards ever faster websites with early hints and priority hints

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 hopes to make better use…

Clearing cache in the browser

Caching assets in the browser is the most common and most obvious way to improve front end performance. But at some point every developer accidentally makes a bad release of an asset with a long…

ButterCMS on building a globally performant + reliable API

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 nearly crippled their business, they became “obsessed”…

Understanding the Vary header in the browser

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 explores the…

Diff at the edge with serverless cloud functions

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 compute services to make your…

The QA mindset: designing for reliability

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) need quality assurance (QA)? In this post,…

Getting more out of IO with image transformation classes

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 image transformation classes…

Server-sent events with Fastly

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 by websites, and whether it’s flight…

Getting the most out of Vary with Fastly

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 this post, we’ll provide…

Introducing batch API for surrogate key purge

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 multiple surrogate keys at…

Optimizing HTTP/2 server push with Fastly

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, h2 traffic has increased…

Leveraging the browser cache with Fastly’s CDN

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 provide….

Cache hit ratios at the edge: a performance study

In an earlier post, we discussed the meaning of cache hit ratio (CHR) and analyzed what the metric is and isn’t telling us, showing why we really need two different CHR metrics (CHRedge and CHRglobal)...

The truth about cache hit ratios

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…

Introducing the Fastly savings calculator

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 customers to save on infrastructure costs. But just…

Google Chrome’s Alex Russell on service workers, PWAs, and what’s next for mobile

At Altitude 2016, Software Engineer Alex Russell discussed the latest projects the “performance obsessed” Google Chrome team had underway. In this recap, we’ll take a look at how you can provide reliable offline experiences, how…

A step towards better Web API authentication

The Fastly API is an integral part of our CDN — using our APIs, customers are able to instantly reflect configuration changes, purge content, and perform anything that is available on the Fastly control panel…

A/B testing at the edge

A/B testing is valuable, aggravating, and everyone has an opinion on the best way to do it. At Fastly, we provide a set of tools to help enable experiments you can integrate into your own…