Sentinel: Your Web-Performance Watchman

CSS Guidelines 2.0.0

Written by on CSS Wizardry.

Table of Contents
  1. An experiment
    1. Reasoning

Some time ago, I published my CSS Guidelines on GitHub. These proved incredibly popular, with thousands of stars, hundreds of forks, and a number of translations. However—as often happens with these kinds of thing—they’re in need of a little bit of spring clean.

I’m going to completely revisit, revise, overhaul, and rewrite the guidelines into a comprehensive version 2.0.0. They will cover new things, they will change old things, and they will be a lot, lot more thorough.

The guidelines will also become a lot more formal; they will have their own dedicated domain,, and will be properly, semantically versioned. This should help them remain more maintainable and current.

Also, given that these things take a long time to put together, and contain a lot of intellectual property, I’ve decided to monetise version 2.0.0, but through a less traditional model…

An experiment

Having seen people like Radiohead and Louis CK experiment with pay what you want models, I’ve decided to try the same: CSS Guidelines will be free to all, available at, but with a voluntary payment plan (provided by Gumroad).

It will be very interesting to see how many people do pay (and how many do not).


I work for myself, my time is money, so taking time out to write these guidelines is an opportunity cost. Further, sharing so much information may actually impact whether someone would need to hire me or not—why get me on site when I’ve written up such comprehensive guidelines?

But, that said, I genuinely do believe in the importance of sharing knowledge—I would rather not have this information behind a solid pay wall. I also donate to free and useful tools myself, as a thank you to the developer(s), and to try and give some small incentive to maintain and stick with the project: I’m hoping that other people do the same.

I’m going out on a limb here, it is a bit of gamble, but I’m hoping that people who do get benefit from the guidelines will support them.

I have already started work on 2.0.0 which you can read (and support) right now at You can get updates on the project and its upcoming chapters by following @cssguidelines.

Now, go get ’em!

Did this help? We can do way more!

Hi there, I’m Harry Roberts. I am an award-winning Consultant Web Performance Engineer, designer, developer, writer, and speaker from the UK. I write, Tweet, speak, and share code about measuring and improving site-speed. You should hire me.

You can now find me on Mastodon.

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