Rewriting All of Spotify's Code Base, All the Time

Abstract

We don't need LLMs to write new code. We need them to clean up the mess we already made.

In mature organizations, we have to maintain and migrate the existing codebase. Engineers are constantly balancing new feature development with endless software upkeep.

But what if you could rewrite your codebase, every single day, across thousands of repositories? What if your engineers didn't have to maintain their code?

At Spotify, we are seeing early success using LLMs to perform predictable, repeatable and effortless code migrations.

In this talk, we’ll share how we created an Agentic Migrator that has gotten over 3000 PRs merged across several engineering disciplines. We will tell you how we reason about solving the complexity of LLMs maintaining code at scale. From managing build feedback loops across thousands of repos, to evaluating prompt effectiveness and mastering the sheer complexity of our diverse codebase.


Speaker

Jo Kelly-Fenton

Engineer @Spotify

Hi! I am Jo – an engineer at Spotify, working on the development and company-wide adoption of autonomous coding agents. Before working at Spotify, I was working on integrating automation into Amazon’s Grocery Warehouse workflows.

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Speaker

Aleksandar Mitic

Software Engineer @Spotify

I'm Aleksandar! I have been working as a Software Engineer at Spotify for 4 years. My tenure at Spotify has been spent within Platform teams. Specifically working on infrastructure for service to service communication and backend developer experience. Most recently I've been working on AI assisted development tooling.

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