Sentinel: Your Web-Performance Watchman


Written by on CSS Wizardry.

Table of Contents
  1. Donations

Over eighteen months ago I wrote an article about a mobile optimised business card I made. Today I finally did something awesome with it! is basically a way of emulating business cards on the web; it’s business card shaped, it contains contact details and it has two sides. You rotate your phone to switch between a bio and your contact details.

I’ve buit on top of inuit.css, packaged up the code and hosted it on GitHub for you to download and create your own theme for. My card can be found over on, turn your phone to see both sides of the card!


I never charge for any of my articles, projects, code, advice, anything. However, as is (in my opinion) a pretty cool idea for an app style project, I’ve decided to require an attribution notice that can be optionally removed by simply donating USD3.99 (GBP2.50) to the project via Gumroad. It’s not a lot of money and I have no aims or goals as far as earnings go, but I think it’s a nice token amount to show your support and to remove the attribution text.

If you do donate then let me know and I’ll add your profile’s URL to the project’s README as an extra little thank you.

Hopefully people will find it pretty cool, I know I do!


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.

Suffering? Fix It Fast!


  • inuitcss
  • ITCSS – coming soon…
  • CSS Guidelines

Next Appearance

  • Talk & Workshop

    WebExpo: Prague (Czech Republic), May 2024


I am available for hire to consult, advise, and develop with passionate product teams across the globe.

I specialise in large, product-based projects where performance, scalability, and maintainability are paramount.