Today's guest is Maude Lemaire, who is a principal engineer at GitHub and author of the book Refactoring at Scale.
With Maude, we talked about:
Her journey in tech, from Rent the Runway to joining Slack and leading its performance engineering team to joining GitHub as a principal engineer.
Then we discussed what it means to do Refactoring at scale, how to do it right, how to bring people on board, and what are the biggest mistakes you should avoid.
This episode is brought to you by Swarmia! The engineering intelligence platform that serves some of the best software companies in the world.
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🎙️ Episode
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🥇 Interview Summary
If you are a 🔒 paid subscriber 🔒 you will find my own summary of the interview below.
It’s the 10-minute, handcrafted takeaways of what we talked about, with timestamps to the relevant video moments, for those who don’t have time to sit through the 1-hour chat.
Here is the agenda for today's episode:
🎓 Maude's Unexpected Journey to Tech (02:17)
🏢 From Rent the Runway to Slack's Growth (09:44)
🔄 Transitioning to GitHub as Principal Engineer (15:40)
🏗️ Tackling Large-Scale Infrastructure at GitHub (26:07)
📖 Refactoring at Scale: Lessons from the Trenches (49:17)
Let's dive in 👇
1) 🎓 Maude's Unexpected Journey to Tech (02:17)
Maude's path to becoming a principal engineer at GitHub started with a completely different plan. As a high school student with detailed five-year plans, she intended to major in microbiology and pursue genetics research.
However, three weeks into her molecular biology class, everything changed. She discovered she loved the algorithmic thinking required in organic chemistry problems — finding the shortest path from one molecule to another.
"What I really liked about those [organic chemistry classes] was that a lot of the problems that we were doing were, 'Here's an initial molecule. Here's the goal molecule. How do you get to it in as few steps as possible?' And you can see there's like an analog to programming."
The twist? Her father was a programmer who worked on embedded systems and assembly code — exactly the type of low-level programming that seemed boring to teenage Maude. She even kept her enrollment in a programming class a secret from him, fearing disappointment if she hated it.
But when chemical engineering didn't work out, computer science became her backup plan. Her father proved invaluable during the challenging early days, helping her understand that while classmates had years of coding experience, she'd eventually catch up in the more abstract algorithmic courses.
2) 🏢 From Rent the Runway to Slack's Growth (09:44)
Maude's professional journey began with internships at Rent the Runway, where she worked under Camille Fournier's leadership. The combination of fashion and technology appealed to her diverse interests, but the West Coast beckoned when her boyfriend (now husband) was working at Microsoft in Seattle.
In true engineer fashion, they decided to both quit their jobs and move to San Francisco — choosing a completely neutral third location to be "fair."
At Slack, Maude experienced something special during the interview process:
"There's like those rare places you interview where you walk out with more energy than you had going in because you're vibing so well with the folks in the interview... I walked out of there and I had this feeling of like I don't even care if I don't get it because I had so much fun."
She joined Slack when it had just over 100 engineers and stayed for nearly eight years, watching it grow to 1,200 engineers through IPO and acquisition by Salesforce. Her team specialized in load testing tooling and performance monitoring, supporting the entire engineering organization with just 3-4 engineers — a masterclass in learning to multiply yourself.
3) 🔄 Transitioning to GitHub as Principal Engineer (15:40)
After eight years at Slack, Maude realized she had accomplished the ambitious vision she'd set for her team four years earlier. The realization came during a planning session when she looked back at her original "manifesto" and discovered they had actually achieved what once seemed like a moonshot.
Several factors influenced her decision to leave:
🎯 Mission accomplished — her team had built the load testing infrastructure she'd envisioned
🔄 End of an era — the original CTO and co-founder Cal Henderson announced his departure
💪 Prove herself elsewhere — the desire to demonstrate her skills in a new environment
