Cassidy Williams
Cassidy Williams
Cassidy Williams
Hi! I’m Cassidy, and I like to make memes and dreams and software. I’m the Senior Director of Developer Advocacy at GitHub! Outside of that fancy title, I’m a startup advisor and investor, open source-er, and meme-maker on the internet. I enjoy building mechanical keyboards, playing music, hanging out with my family and friends, and teaching in my free time.
Latest Posts
If you haven’t seen it yet, one of my open source projects that I’ve been “maintaining” for a while is called todometer. It’s a glorified to-do app with a progress bar, in a desktop app. It’s built with Electron and React, and I first...
Last week, I had the pleasure of speaking at Codemotion Madrid! The event was really cool. I think I heard the organizers say that there were at least a couple thousand developers there, and there were multiple talk tracks throughout. I...
I’ve been using an Elgato Stream Deck to control my lights in my office for the past several years. The one I have (with 15 buttons) has worked great for me, but I noticed that I only really use 8 of the buttons. The rest work perfectly...
I gave the opening keynote at Deep Dish Swift 2026 today! It was so fun. The event is very iOS-oriented and nearly 300 people in the Chicago area, and it was cool meeting so many folks who I hadn’t met in person before. Before the event,...
I just got home from South Korea, where I taught some workshops at an event hosted by the U.S. Embassy Seoul! The event is called TechCamp Korea 2026, and the participants were a cohort of young professionals, entrepreneurs, and...
My sister got me a rainbow cardigan sweater a couple years ago for Christmas that is very fluffy and floppy. It doesn’t have pockets, it doesn’t have buttons, it just kind of drapes on me and is like a small blanket with arms. It’s not a...
I talked about building my Micro Journal in the past here, and how much I like having a distraction-free writing device for blogging, drafting things, and just getting ideas out. Well… I liked it so much that I got another one! This one...
I recently updated my app todometer to be styled with pure, native CSS! Styling todometer over time Changing the CSS libraries in todometer has been a real reflection of CSS styling history. When I first built it more than 9 years ago...
My poor Sony a6100 camera (with a Sigma 30mm lens) died on me this week. It served me well for over 6 years! I replaced it with my husband’s a6400 that he wasn’t using anymore, and because of various adjustments on my desk that I made at...
I found this old article about making wavy lines with CSS, and decided to play around with it! Here’s the final result: See the Pen Wavy diving board by Cassidy (@cassidoo) on CodePen. It’s not the most gorgeous art in the world, but it...
I’ve been asked a couple times just this week how passkeys work, here’s a little rundown! What passkeys are and how they work The “sales pitch” for passkeys is that they’re like a password that you will never know, and can never leak....
I’ve always loved making videos. Not because I love being on camera, but I really enjoy putting together jokes and stories and tutorials (etc) with video as a medium. The moment I had the ability to plug a camera into a computer back in...
When it comes to certain projects, I like “doing things that don’t scale.”, particularly with my newsletter. I noticed that my newsletter open rate was down over the past few months to about 40-45%. Not bad, but not as good as it once...
I stumbled upon the CSS property corner-shape recently and it’s pretty cool. It allows you to specify the shape of an element’s corners and works with border-radius. I threw together this demo to show it in action: See the Pen...
I switch back and forth between Windows and Mac pretty regularly depending on what I’m working on (and sometimes between WSL and PowerShell on the same machine, what a time to be alive), and one thing that I always mess up in PowerShell...