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

QCon London 2026

Session AI

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

Tuesday Mar 17 / 11:45AM GMT, Fleming (3rd Fl.) at The QEII Centre, London

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.

Topics

AI Platform Engineering DevEx
76% senior dev or higher
1:11 speaker ratio
60+ practitioners

QCon London 2026 is a three day conference for senior software engineers, architects and team leads. An international program committee of working engineers selects every session. Patterns and practices, not products and pitches.

Share

From the same track

Tuesday 17 March

10:35 Whittle (3rd Fl.) Session AI/LLM Reliable Retrieval for Production AI Systems Lan Chu AI Tech Lead and Senior Data Scientist 11:45 Fleming (3rd Fl.) Session AI Rewriting All of Spotify's Code Base, All the Time Jo Kelly-Fenton, Aleksandar Mitic 13:35 Churchill (Ground Fl.) Session AI/ML Refreshing Stale Code Intelligence Jeff Smith CEO & Co-Founder @Neoteny AI, AI Engineer, Researcher, Author, Ex-Meta/FAIR 14:45 Churchill (Ground Fl.) Session AI Beyond Context Windows: Building Cognitive Memory for AI Agents Karthik Ramgopal Distinguished Engineer & Tech Lead of the Product Engineering Team @LinkedIn, 15+ Years of Experience in Full-Stack Software Development 15:55 Fleming (3rd Fl.) Session applied ai Building an AI Gateway Without Frameworks: One Platform, Many Agents Amit Navindgi, Jatin Aneja 17:05 Whittle (3rd Fl.) Session Async Agents in Production: Failure Modes and Fixes Meryem Arik Co-Founder and CEO @Doubleword (Previously TitanML), Recognized as a Technology Leader in Forbes 30 Under 30, Recovering Physicist