Simon Hearne

Web Performance Consultant

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Giving Great (Remote) Software Demos

Giving great software demos is both science and art. Here are some tips on making the most out of every demo opportunity, even when you're stuck at home!

Who Opts-in to Save-data?

A primer on save-data, what it means for your users and what it means for you.

Measuring Performance behind consent popups

Opting in to cookies can load multiple megabytes of additional content. Here are tips on how to measure web performance both with and without cookie consent.

When Network is Faster than Cache

We assume that browser caches are near-instantaneous, but data shows that retrieving an object from cache can take hundreds of milliseconds!

Is it time for a Web Performance rebrand?

Web Performance is a niche term in a broad market, should we widen our appeal to reach more people?

Collecting SmartThings data in InfluxDB on Raspberry Pi

How to collect data from your Home Automation system into a local timeseries database.

Collecting SpeedTest results in Influx on Raspberry Pi

How to set up regular SpeedTest reports into a local InfluxDB on a Raspberry Pi

Reporting Raspberry Pi System Metrics to InfluxDB

How to set up regular system stat reports from a Raspberry Pi into a local InfluxDB

Installing InfluxDB & Grafana on Raspberry Pi

I recently treated myself to a RaspberryPi 4 Model B to use as a(nother) home server. This is a brief guide on getting InfluxDB and Grafana set up to store a...


HTTP Headers for fast & secure static sites

An introduction to key HTTP response headers for speed and security, with implementation guides for Netlify & CloudFlare

Six Web Performance Technologies to Watch in 2020

Don't bet on 5G and HTTP/3 to make things faster, there are six technologies that I believe will have a bigger impact on web performance in 2020.

Native image lazy loading has landed in Chrome, maybe don't use it

Native lazy loading for iframes and images landed in Chrome 76, but don't go ripping out your existing lazy loading strategy just yet.

WebPageTest Private - 'no successful results'

A potential quick fix for "The test completed but there were no successful results." in WebPageTest private instances.

Why Site Speed is Critical for Online Publishers

Site speed is a critical factor in the success of an online publishing business, whether revenue is driven by adverts or subscriptions. This post demonstrate...


Lead Developer Conference (London) - Day 1!

Lead Developer is a conference for senior and lead software engineers. These are my raw notes from day one.

Delta V Conference - Day 2!

Delta V Conference is a new two-day, single-track web performance conference in London, hosted by me, Perry Dyball and Jo Franchetti. Here's my raw notes fro...

Delta V Conference - Day 1!

Delta V Conference is a new two-day, single-track web performance conference in London, hosted by me, Perry Dyball and Jo Franchetti. Here's my raw notes fro...


Twitter Lite isn't as good as the app, and that's okay

Twitter's Progressive Web App is finally out of testing, and it's not as good as the native app. Missing push notifications, wonky images, small text boxes, ...

Your Analytics Lies to You

You can't rely on your web analytics for performance data and it's understating bounce rate and traffic numbers from old devices.

How to Optimise CSS Image Sprites

Optimising sprites might be more important than you think, and easier than you expect!


Three WebPerf Takeaways from Velocity Europe

Velocity Amsterdam has just come to a close. Here are the three key things that I am taking away from the two days of sessions.

Velocity NY 2016 - Wrap-up

Velocity New York seems like a distant memory now, especially with Velocity Europe around the corner. With that said, I have copious notes from the two day c...

Blocking requests in webpagetest? Don't use Chrome.

We know that third-party content can harm the user experience on a website. Measuring that impact can be tricky.

How fast is fast enough?

Do you know when your website’s speed starts to impact your customers’ behaviour?

Getting Reliable Visual Performance Metrics

Tips to get more reliable & consistent visual metrics from WebPageTest

Render Conf 2016

Render Conference - previously known as jQuery UK - was held in Oxford last week. It's a front-end conference for front-end people, which makes me a bit of a...

Prioritising Site Speed Recommendations

Sometimes prioritising recommendations is more important than making them.


Velocity Europe 2015 - The Good Ones!

This post is a review and summary of the talks at Velocity Europe that I attended. I've summarised each talk and given links to the slides, videos and rating...

Velocity Europe 2015 - My Allstars

This post is a review and summary of the talks at Velocity Europe that got a 5 star review from me. I've summarised each talk and given links to the slides, ...

Measuring Webpage Jank

Webpage jank can harm the user experience, here's an easy way to measure it on your pages

Be Mindful With Modernizr

Modernizr might be making your site slow, especially on mobiles

The Future of Web Performance - Part 1

Web performance is critically important, how will upcoming technologies change the way we manage it?

Questions to Ask Your Third-Parties

We need rules to keep third-party Javascript in check.

Manage Third-party Risk Using a Content Security Policy

A feature to prevent cross-site-scripting may make it easier to police third-party javascript.

Using a Web Performance Heatmap to Assess Page Performance

I've made a Heatmap to visualise when each element loads on a page.

How to Find the Third-Parties on Your Site

Third-party means not you or me, but them.

Web Performance Optimisation Basics

Website performance is critical to user experience. We need rules to make it easier.