In this episode of Tern Stories, I spoke with Maude Lemaire about a migration that started with SQL and ended with people taking shifts at dawn.  

She joined Slack less than two years out of college, and within months, she was leading a core part of the company’s efforts to keep up with their biggest customer, IBM. The project: unifying Slack’s channel membership model—one of the most central, performance-sensitive parts of the product.

At one point, the system was so fragile that engineers had to be in the office at 6 A.M. every day, just to watch IBM’s login spike and make sure the system didn’t collapse.  

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Go check out what Maude does! ➡️ https://maudethecodetoad.com/  

Her book, Refactoring at Scale, is available now 📖: https://www.oreilly.com/library/view/refactoring-at-scale/9781492075523/  

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Slack's 6am Database Club | Ep. 9

If you’ve worked on more than one code migration, you already know the punchline: none of them are the same.  

Sure, it sounds like a React 17 → 18 upgrade should follow the same plan for everyone.   

But a real-world code migration always find a way to be uniquely painful. Your app uses different corners of the library.  

Your plugin stack has its own fingerprint.  

Your engineers wrote some “just for now” code that’s still running five years later.  

Whatever you thought the code migration would be, it won’t be.  

This was one of the biggest takeaways in a recent episode of Tern Stories, where we looked inward for once.  

My cofounder Ryan and I talked through what we’ve seen in our own migrations and the ones we’ve supported across companies.  

Despite the variety, a few consistent truths emerged.

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Why Every Code Migration Feels Different (and What to Do About It) | Ep. 8

Alright, picture this. It's March 2020. Everybody just went to work from home. You work at Slack, which is suddenly one of three applications keeping the entire business world connected.  And nobody owns Memcache.  

Today's episode of Turn Stories is with Glen Sanford, who decided he was going to own Memcache and he was going to migrate it.  

I am stretching that word today.  

Whether you're an aspiring engineer or a seasoned professional, Glen's insights will inspire you to take ownership of your projects and strive for continuous improvement!

Migrating Memcache in a time of DEMAND | Ep. 07

In this episode of Turn Stories, I sit down with Anthony Sottile, who led Lyft's migration from Python 2 to 3.  They did 150 services in less than six months. But what stood out wasn't just the scale or the timeline, it was the approach.  

They really leaned on tooling so they could ratchet progress forward, and then they'd lock it in with CI rules so nothing backslid.  

They would ship automated PRs, and if nobody complained but nobody looked at them, they would just purge them, and they trusted their infrastructure.  

They would do deployments where even if there were errors, they knew the system would retry, and there wouldn't be any user visible impact.  

And that made for a really powerful migration story. So we talk about what worked, we talk about what didn't, and some of the most hilarious failures across a couple of key services.  -----  

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Go subscribe to Anthony! ➡️ https://www.youtube.com/anthonywritescode

Ratcheting Progress: How Lyft Migrated 150+ Services from Python 2 to 3 | Ep. 6

“If I could wipe out one technology? TCP/IP.”  

 That was Mike Jervis’ answer. He was half-joking. Sort of.   

Mike’s a cybersecurity and privacy lawyer at Mullen Coughlin. He works with companies after the worst has happened—when ransomware locks down production, customer data is exfiltrated, and legal deadlines start ticking. His job is to figure out what broke, what the law demands, and how to respond.  

This episode of Tern Stories is about the aftermath of a breach. What’s surprising isn’t just the chaos—it’s how much of the outcome hinges on infrastructure, habits, and technical decisions made months or years before the incident.  

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What Litigation Teaches Us About Security Operations | Ep. 5

What does it take to replace the core data store at a company like Datadog? 

That's the question I asked Ian Noland, who led Datadog's migration from Elasticsearch to a new system called Husky.  

In this insightful conversation, Ian shares the challenges and triumphs of this monumental task, including why APM was the first product to move, how they used Kafka to run both systems in parallel, and the importance of deliberately preserving a system's bugs.  

Join us as we delve into the world of observability and data management, and discover how Ian and his team successfully navigated this challenging journey.  

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Outscaling ElasticSearch at Datadog | Ep. 4

When Postgres 11 approached end-of-life, a major travel company brought in site reliability engineer Ninad Pundalik to lead the upgrade. The setup: multiple Ruby on Rails apps, with multiple Postgres 11 instances on AWS RDS. No in-house infra team.  

No clear ownership. Some tables still in use, others long forgotten.  

Despite the uncertainty, the migration went smoothly. The team cut over cleanly, avoided downtime, and ended up with a simpler, more reliable setup than they started with.  

Get Tern Stories in your inbox: https://tern.sh/youtube [https://www.youtube.com/redirect?event=video_description&redir_token=QUFFLUhqbnZCWjNHTExNQVRuWm45b2RQZ05TZG9QczZqZ3xBQ3Jtc0tsYjBRcWc4ZmNTTzdOSldlaHdkbjBiZVBZNEpXdXVHeGtncGRKRHpwNFpwQ2dBY01CZVltRWZFMjBrZ3p5ZmtuU0cxdVBJVVVxZXRzWHFjckRsLXl4Mm1KcTJyMENKb2lQclBDUmlfQ1hBdHo5cVk3WQ&q=https%3A%2F%2Ftern.sh%2Fyoutube&v=1fOW3THZHOo]

Upgrading Postgres: 5 Versions Behind, 4 Databases to Merge | Ep. 03

Hal Anil, Staff Engineer at Braze, joined just as the company hit a turning point: KnockOutJS and CoffeeScript were no longer cutting it. In this episode of Tern Stories, Hal walks through how they migrated to React and TypeScript—without pausing product work or losing developer trust.

We talk about:
• Why they started with workshops, not code
• How a single collapsible UI unlocked momentum
• The real value of tooling (hint: it’s not automation)
• Making migrations feel safe, even exciting

Quitting CoffeeScript? First Teach Everybody Typescript | Ep. 02

Yesterday, I got the chance to talk with Matt Ouille about their code migration of a critical internal service, their service catalog, and how they moved it from a struggling Python monolith to an event-driven architecture.   

This code migration journey was not just a technical challenge; it was a transformative experience that turned reluctant stakeholders into enthusiastic champions of change.   

If you've ever felt trapped by tech debt or wondered how real-world teams overcome messy scaling problems, this episode is for you.  

Get Tern Stories in your inbox: https://tern.sh/youtube [https://www.youtube.com/redirect?event=video_description&redir_token=QUFFLUhqa21qZVE0b2pTOEZyT21LY1c0WC1sLUpvdjkwUXxBQ3Jtc0ttZExlR3RaY01DeGh5azBsYnJteVZ0X3JTRFJreFNvOXB0eG45UnEyT2RmTDVYUzN4cEdSY0ZYWV8ybVBES09VV0dMcnhQVVF5c1lxaFZQUkZoQml3SWI5ZUdUbUtHa0VYQ3NCYkxuZXM3X2FqNldjdw&q=https%3A%2F%2Ftern.sh%2Fyoutube&v=nYVVmDIZKuw]

The Human Side of Code Migration | Ep. 01

The future of AI isn’t just new code; it’s evolving the code you already have. Tern Stories is conversations with engineers about how tackled their toughest migrations.

Want to tell your migration story, or learn how to make your migrations fast, safe, and predictable? Say hi at hello@tern.sh. 