Cassidy
@cassidoo.co
Making memes, dreams, & software!
Sr. Director of Dev Advocacy at GitHub. Married to a dweeb and mom to a nerdy toddler + baby combo. She/Her ✝️ CHI 🏠
Subscribe to my newsletter!
cassidoo.co/newsletter
Sr. Director of Dev Advocacy at GitHub. Married to a dweeb and mom to a nerdy toddler + baby combo. She/Her ✝️ CHI 🏠
Subscribe to my newsletter!
cassidoo.co/newsletter
Pinned
Cassidy
@cassidoo.co
· Nov 4
Cassidy Williams
I'm Cassidy Williams, a software engineer, mom, and overall nerd in Chicago. I write about tech, projects, and whatever else I'm thinking about!
cassidoo.co
Hey new friends!
I'm Cassidy, based in Chicago.
I work at @github.com, and I love building projects, advising startups, helping people learn, and making memes.
Most of my work is open source, and I have a weekly newsletter and blog at cassidoo.co. Check it out, and see you around!
I'm Cassidy, based in Chicago.
I work at @github.com, and I love building projects, advising startups, helping people learn, and making memes.
Most of my work is open source, and I have a weekly newsletter and blog at cassidoo.co. Check it out, and see you around!
Reposted by Cassidy
corner-shape is one of those things where when you first see it, it's like "oh cool, I can make a scoop!" It's something new, which is fun, but it can be hard to think of good use cases.
But, as @cassidoo.co looks at here, it's going to open up a lot of possibilities 🙂 cassidoo.co/post/css-cor...
But, as @cassidoo.co looks at here, it's going to open up a lot of possibilities 🙂 cassidoo.co/post/css-cor...
Making interesting borders with CSS corner-shape
You can make cool beveled, rounded, notched, scooped, and elliptical borders with the new CSS corner-shape property!
cassidoo.co
February 5, 2026 at 12:49 PM
corner-shape is one of those things where when you first see it, it's like "oh cool, I can make a scoop!" It's something new, which is fun, but it can be hard to think of good use cases.
But, as @cassidoo.co looks at here, it's going to open up a lot of possibilities 🙂 cassidoo.co/post/css-cor...
But, as @cassidoo.co looks at here, it's going to open up a lot of possibilities 🙂 cassidoo.co/post/css-cor...
February 5, 2026 at 7:08 PM
February 5, 2026 at 6:11 PM
February 4, 2026 at 5:10 PM
Reposted by Cassidy
Happy February!
First newsletter issue of this perfect month (that's a reference to the practice coding question 👀) is out!
cassidoo.co/newsletter
First newsletter issue of this perfect month (that's a reference to the practice coding question 👀) is out!
cassidoo.co/newsletter
rendezvous with cassidoo
A weekly newsletter with web development content for everyone, from beginners to pros.
cassidoo.co
February 2, 2026 at 8:31 AM
Happy February!
First newsletter issue of this perfect month (that's a reference to the practice coding question 👀) is out!
cassidoo.co/newsletter
First newsletter issue of this perfect month (that's a reference to the practice coding question 👀) is out!
cassidoo.co/newsletter
Reposted by Cassidy
We hear the questions constantly: Does AI actually help, or is it just hype? 🤔
So @cassidoo.co dug into the feedback to find out what developers really use AI for, and where it makes the biggest difference in their work.
Here's what she discovered. ⬇️
So @cassidoo.co dug into the feedback to find out what developers really use AI for, and where it makes the biggest difference in their work.
Here's what she discovered. ⬇️
What AI is actually good for, according to developers
Discover how developer feedback and real-world experience are shaping AI coding tools that keep you in control.
github.blog
February 3, 2026 at 5:50 PM
We hear the questions constantly: Does AI actually help, or is it just hype? 🤔
So @cassidoo.co dug into the feedback to find out what developers really use AI for, and where it makes the biggest difference in their work.
Here's what she discovered. ⬇️
So @cassidoo.co dug into the feedback to find out what developers really use AI for, and where it makes the biggest difference in their work.
Here's what she discovered. ⬇️
I am devastated to learn in 2026 that PowerShell and Windows PowerShell are two different products
February 3, 2026 at 3:14 PM
I am devastated to learn in 2026 that PowerShell and Windows PowerShell are two different products
Reposted by Cassidy
Happy February!
First newsletter issue of this perfect month (that's a reference to the practice coding question 👀) is out!
cassidoo.co/newsletter
First newsletter issue of this perfect month (that's a reference to the practice coding question 👀) is out!
cassidoo.co/newsletter
rendezvous with cassidoo
A weekly newsletter with web development content for everyone, from beginners to pros.
cassidoo.co
February 2, 2026 at 8:31 AM
Happy February!
First newsletter issue of this perfect month (that's a reference to the practice coding question 👀) is out!
cassidoo.co/newsletter
First newsletter issue of this perfect month (that's a reference to the practice coding question 👀) is out!
cassidoo.co/newsletter
In "doing things that don't scale" news, I noticed that my newsletter open rate was down over the past few months to about 40-45%, and I tried a very manual thing to increase it: I asked for help??
Anyway, it worked, and now it's in the mid-50s again ✨
cassidoo.co/post/do-not-...
Anyway, it worked, and now it's in the mid-50s again ✨
cassidoo.co/post/do-not-...
Improving my newsletter's open rate the hard(er) way
Turns out just asking for help gets you help? Who knew? Here's how I increased my newsletter open rate.
cassidoo.co
February 2, 2026 at 6:14 AM
In "doing things that don't scale" news, I noticed that my newsletter open rate was down over the past few months to about 40-45%, and I tried a very manual thing to increase it: I asked for help??
Anyway, it worked, and now it's in the mid-50s again ✨
cassidoo.co/post/do-not-...
Anyway, it worked, and now it's in the mid-50s again ✨
cassidoo.co/post/do-not-...
Reposted by Cassidy
We have a perfect Rectangular February coming up, first time we’ve had one since 2015
Maybe this is what finally closes the loop and fixes the world
Maybe this is what finally closes the loop and fixes the world
January 31, 2026 at 11:28 PM
We have a perfect Rectangular February coming up, first time we’ve had one since 2015
Maybe this is what finally closes the loop and fixes the world
Maybe this is what finally closes the loop and fixes the world
Reposted by Cassidy
How @cassidoo.co writes consistently for 8 years
January 31, 2026 at 1:19 AM
How @cassidoo.co writes consistently for 8 years
Reposted by Cassidy
Great demo of GitHub's new semantic search functionality for Issues. (It's in preview so you can get an early look!). Watch Cassidy walkthrough on how to use human language to search for the GitHub Issues you care about....
Today at @github.com we're rolling out a new issues search in preview.
In internal testing, the average list position has improved by 39% with the new semantic search in addition to returning more matching results!
Check out this side-by-side comparison in this popular repo from Home Assistant:
In internal testing, the average list position has improved by 39% with the new semantic search in addition to returning more matching results!
Check out this side-by-side comparison in this popular repo from Home Assistant:
January 29, 2026 at 5:36 PM
Great demo of GitHub's new semantic search functionality for Issues. (It's in preview so you can get an early look!). Watch Cassidy walkthrough on how to use human language to search for the GitHub Issues you care about....
Reposted by Cassidy
How does it feel for one to be seen? Well that's a bit philosophical for me to answer in a blog post, so just debate me in the replies.
Instead I built upon a post from @cassidoo.co, with a tip and a prompt to have your website *seen* by generative search engines like ChatGPT, Claude, and Gemini.
Instead I built upon a post from @cassidoo.co, with a tip and a prompt to have your website *seen* by generative search engines like ChatGPT, Claude, and Gemini.
Updating Your Website For Generative Engine Optimization
Learn how to optimize your website for generative search engines like ChatGPT, Claude, and Gemini to improve your search engine rankings.
build.ms
January 29, 2026 at 3:50 PM
How does it feel for one to be seen? Well that's a bit philosophical for me to answer in a blog post, so just debate me in the replies.
Instead I built upon a post from @cassidoo.co, with a tip and a prompt to have your website *seen* by generative search engines like ChatGPT, Claude, and Gemini.
Instead I built upon a post from @cassidoo.co, with a tip and a prompt to have your website *seen* by generative search engines like ChatGPT, Claude, and Gemini.
Reposted by Cassidy
yesterday @cassidoo.co taught me how to use the Copilot CLI. we built a small API to let people vote on which of us is funnier (obviously me), then created a Twitch bot that used the API to let you all add votes live — pretty cool stuff happening here
watch the episode: codetv.dev/series/learn...
watch the episode: codetv.dev/series/learn...
GitHub Copilot CLI (and SDK) | Learn With Jason Series 9
Learn the GitHub Copilot CLI from Sr. Director of Developer Advocacy Cassidy Williams.
codetv.dev
January 28, 2026 at 11:17 PM
yesterday @cassidoo.co taught me how to use the Copilot CLI. we built a small API to let people vote on which of us is funnier (obviously me), then created a Twitch bot that used the API to let you all add votes live — pretty cool stuff happening here
watch the episode: codetv.dev/series/learn...
watch the episode: codetv.dev/series/learn...
check out our very professional podcast episode
January 30, 2026 at 5:42 PM
check out our very professional podcast episode
Reposted by Cassidy
@cassidoo.co doesn't miss an opportunity
January 27, 2026 at 5:09 PM
@cassidoo.co doesn't miss an opportunity
Check out this keeb I built
January 30, 2026 at 3:47 PM
Check out this keeb I built
cassidoo - Twitch
brain no work, but must work, let us code and stuff
www.twitch.tv
January 29, 2026 at 8:59 PM
Streaming on GitHub's channels if you wanna come cowork and hang out!
www.twitch.tv/github
www.youtube.com/watch?v=7uza...
www.twitch.tv/github
www.youtube.com/watch?v=7uza...
January 29, 2026 at 7:04 PM
Streaming on GitHub's channels if you wanna come cowork and hang out!
www.twitch.tv/github
www.youtube.com/watch?v=7uza...
www.twitch.tv/github
www.youtube.com/watch?v=7uza...
Today at @github.com we're rolling out a new issues search in preview.
In internal testing, the average list position has improved by 39% with the new semantic search in addition to returning more matching results!
Check out this side-by-side comparison in this popular repo from Home Assistant:
In internal testing, the average list position has improved by 39% with the new semantic search in addition to returning more matching results!
Check out this side-by-side comparison in this popular repo from Home Assistant:
January 29, 2026 at 5:28 PM
Today at @github.com we're rolling out a new issues search in preview.
In internal testing, the average list position has improved by 39% with the new semantic search in addition to returning more matching results!
Check out this side-by-side comparison in this popular repo from Home Assistant:
In internal testing, the average list position has improved by 39% with the new semantic search in addition to returning more matching results!
Check out this side-by-side comparison in this popular repo from Home Assistant:
Reposted by Cassidy
The industry is learning a lot right now. From AI and @cassidoo.co
January 29, 2026 at 1:22 AM
The industry is learning a lot right now. From AI and @cassidoo.co