Kilian Valkhof

Front-end & user experience developer, Jedi.

Using easing for more than just CSS transitions

CSS & HTML, 6 January 2020

We can define easing curves for the transitions and animations on our websites to give them a more natural and subtle feel. But it’s not just animations that benefit from easing curves. Any time there is a transition between two states an easing curve will make that feel more natural and less harsh.

Make Your Electron App Feel at Home Everywhere

Electron, 16 December 2019

I got invited to talk about Electron at QCon San Francisco in November and the video and transcript of the presentation are now available. Electron gives you the power to write a single application for Windows, MacOS and Linux. But Electron apps can easily feel out of place among other applications, exactly because you have so much freedom in designing your UI.

The box model is not layout

Design, 8 October 2019

One term that keeps coming up in the design community as a stand-in for layout is “box model”, for example in “Why don’t design tools have the box model?” The CSS Box model is a well-defined term though, and it does not do layout.

If we keep referring to our imaginary perfect layout system in design tools as “box model”, we risk getting the wrong thing.

Superposition: use the design system you already have

Design, 13 August 2019

Having a design system is like having a super power. It takes away all the small decisions you have to make about a design and lets you focus on the higher level goals you have for your design. But creating a design system is a labour intensive process usually only worth it for product teams at large companies or startups.

Notarizing your Electron application

Electron, 4 June 2019

Starting with MacOS 10.14.5, all signed applications by ‘new’ developers will need to be notarized or they will trigger Apple’s Gatekeeper software and prevent users from installing your app. That means that aside from signing your application, you will need to notarize it as well. This is how to successfully notarize your Electron application.

Polypane browser for responsive web development and design Hi, I'm Kilian. I make my living building Polypane, the browser for responsive web development and design. If you're reading this site, that's probably interesting to you. Please try it out!

I develop more software and tools:


Use the design system you already have


A cross-platform, simple and smart autosaving scratchpad.

A Messenger Adventure!

Go on a text adventure in Facebook Messenger.


The latest Electron news, articles, apps and interviews.


Drag-and-drop lossless compression of PNG and JPG images for web.

Messenger Demo Viewer

Demo your (bot) interactions on Messenger.