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Zoompf's Web Performance Blog

Content Detection: A wretched hive of scum and villainy

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A few days ago, I wrote about how the BBC was serving a BMP image as a JPEG. Several people have asked me why would this even work at all? The file extension and the MIME Type both implied it was a JPEG, but the file wasn’t a JPEG. How could the browser even render [...]

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From Performance Issue to Bug to 3 New Features

“It has to be a bug” I thought. “This makes absolutely no sense!” We were about to go live with a major new product, and I had just found what looked like a show-stopping bug. But it wasn’t a bug. In fact, it was something so odd and cool, I ended up creating 3 new [...]

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Debug Your Performance Defects with Zoompf Alerts

In this post I wanted to highlight some of the great free tools now available to our Zoompf Alerts beta users for debugging and fixing performance defects. (And if you’re not on the beta, it’s still not too late to sign up!) Understanding the Problem The first step to fixing a problem is of course [...]

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Visualizing image optimizations with hex editors and strings

I’m a big fan of image optimizations, and have written several posts about it. Images dominate the web in terms of both byte size and request count. Luckily, they are super easy to optimize with free and/or open source tools. For lossless image optimization, you can expect to consistently reduce the size of your image [...]

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Tips to Reduce Your Performance Alert Email Frequency

As your website evolves, it’s inevitable your focus on site performance optimization will ebb and flow. During a new project you may be highly focused on the performance of a new feature, but then after the code deploys and the PR goes out, you settle into maintenance mode, monitoring for regressions until the next big [...]

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A New Way to Justify Your Ongoing Performance Improvement Efforts

There are many great tools out there to measure your current website performance, among them WebPageTest, Google Pagespeed, and of course the Zoompf Free Report. These are fantastic tools for capturing the current state of your website, but all lack one common shortcoming: they provide no historical context of how much better (or worse) your [...]

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SPDYCheck’s New Features: HSTS and Custom Ports

I’m happy to announce a new version of SPDYCheck with a number of improvements. SPDYCheck is an online tool that verifies the many different things a website must do to support SPDY. SPDYCheck also tests a test for best practices which ensures SPDY is used whenever possible. In the last 2 years since SPDYCheck was [...]

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Too Many Performance Defects? 4 Ways to Cut Down the Noise

Time is always a challenge for the performance-minded web developer. You’d love to spend all day tuning your site, but competing priorities are an unavoidable fact of life. When we announced our new Zoompf Alerts beta last week, we mentioned one of the primary goals of Zoompf Alerts was to Find only the performance problems [...]

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Passing Around the DevOps Hat – Help from The Terminator

Last year I posted an article on the growing DevOps movement, the focus on bridging the gap between development and technical operations teams to improve stability, performance and scalability of your website. It certainly takes some time to change the course of a big ship, but in our discussions at Zoompf we’ve been pleasantly surprised [...]

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SSL Performance Diary #2: HTTP Strict Transport Security

This post part of a series, where I discuss the steps I am taking to implement SSL on a website while simultaneously improving its performance. I previously discussed optimized SSL certificates. Today I’ll discuss a super easy SSL performance optimization that everyone should be doing: HTTP Strict Transport Security. When we were designing the web [...]

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