Tern Stories

Code migration is transforming how modern software is built, but few are talking about the risks that come with it. In this episode, we explore how code migration is reshaping API security, infrastructure, and the very foundations of enterprise development. From GraphQL to AI-driven architecture, we uncover what’s really happening behind the buzzwords, and why companies are struggling to keep thei...

In this episode, we dive into Snapchat’s bold code migration, a project that reshaped the way their app runs at scale. This code migration wasn’t just about rewriting code, it was about survival, speed, and creating a leaner system that could handle hundreds of millions of users. You’ll hear how the team faced challenges like supporting long-dead features, rebuilding APIs bug-for-bug, and even mig...

Code migration is one of the toughest challenges engineers face at scale. In this episode, we dive deep into a real-world code migration that powered millions of queries daily. You’ll hear how Sourcegraph rebuilt their core parser, the testing strategies that prevented disasters, and why “unglamorous engineering” is often the work that matters most. From differential testing to temporary safety ne...

Code migration isn’t hard because the code is complex, it’s hard because the real problems only reveal themselves once you’re already in the middle of it. In this episode, I break down why code migration projects so often drag on for months or years, and how AI can change that story completely. From Stripe and Pinterest to Airbnb, Zapier, Twitter, and Slack, you’ll see how teams faced huge migrati...

When a critical code migration goes wrong, the stakes can be nothing short of catastrophic. In this episode, we dive into the code migration that almost brought one of the world’s largest social platforms to its knees. You’ll hear the inside story of how engineers raced against time to prevent total failure, the technical hurdles that made this code migration uniquely challenging, and the high-pre...

Code migration isn’t just a technical task, it’s a minefield. In this episode, we dive into a real-world code migration story from Slack that uncovered terrifying truths lurking deep in the system. From multi-user duplication chaos to security incidents hiding in plain sight, this is code migration at its most high-stakes. You’ll hear how Slack’s “Storm Chasers” team tackled six massive code migra...

Code migration sounds like a technical task, but it’s a strategic minefield. In this episode, we explore how code migration projects fail not because of bugs, but because of broken decision-making and unclear architecture. You’ll hear about raw stories from engineers at Slack, Datadog, and other world-class teams who’ve battled through the chaos of code migration under pressure. If you’re relying...

Code migration sounds like a technical task, but it’s a strategic minefield. In this episode, we explore how code migration projects fail not because of bugs, but because of broken decision-making and unclear architecture. You’ll hear about raw stories from engineers at Slack, Datadog, and other world-class teams who’ve battled through the chaos of code migration under pressure. If you’re relying...

Code migration doesn’t have to be slow and painful. In this episode, Madeline and I break down a proven method to speed up your code migration process without sacrificing code quality or stability. You’ll learn actionable insights from a real-world team who successfully tackled code migration at scale, and did it faster than most thought possible! If you’re planning a code migration, currently in...

Tom Elliott joined Yext in 2015 as an iOS developer. Within a year, both his mobile projects were canceled. But Tom's career crisis was nothing compared to what was happening with Yext's infrastructure.  The company was hitting the limits of homegrown tools built by ex-Google engineers who had recreated their own version of Borg called Khan. It worked when Yext was small. Now they were runnin...

IBM was dropping RethinkDB support. No migration path. No alternatives. Just an end date. Andy Monroe's team at LaborChart had five engineers and an entire construction scheduling platform built on a database that was already dead. They'd watched every other RethinkDB hosting provider shut down, leaving only Compose.io. When IBM acquired Compose, they knew it was just a matter of time. Andy's air...

Back in 2011, PagerDuty had a problem that would make any infrastructure engineer wince: they were using MySQL as a queue.  In this episode, we dive into the fascinating journey of using Cassandra as a queue, the challenges faced, and the lessons learned along the way. Arup Chakrabarti, former Senior Director of Engineering at PagerDuty, shares his insights on the early days of the company, t...

In this episode of Turn Stories, I dive deep into my experiences with Bobby Grayson, the first engineer at Quantierra, a YC-backed startup. Bobby shares his journey from the chaos of WeWork to the unique challenges of a small startup, where he faced a messy codebase and low reliability.  We discuss the impressive app he helped build, which aggregates vast amounts of data from New York City, a...

In this episode, Cooper Bethea, a senior staff engineer at Slack, shares his journey of transforming Slack's architecture to a cellular model, allowing for more resilient operations. Cooper recounts the frustrations of dealing with outages and the decision-making process that led to the migration to a cellular architecture. He explains how the initial struggles with service discovery and load bala...

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...

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...

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.  ...

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...

“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...

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 paral...

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 o...

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...

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 o...