From legacy systems to AI infrastructure: Lessons learned from the WAD World Congress 2025
We just spent three unforgettable days at the WeAreDevelopers World Congress 2025 in Berlin, Europe's main annual gathering for software developers. Our colleagues Khach Gejagezyan, Sascha von Brevern and Alexander Lapitski joined thousands of tech enthusiasts from around the world — united by a shared love for innovation, curiosity, and meaningful connection.
With countless sessions running in parallel, choosing which one to attend was no easy feat. All talks were recorded, giving everyone the chance to revisit and catch up on what they missed.
Highlights from the Event
Here are a few standout highlights from the DEVnet team's experience:
- Tobias Scholz of the tech consultancy Innoq demonstrated how to build a framework-independent component library using WebComponents, Lit, and Vite.
- Dr. Werner Vogels, VP and CTO at Amazon, shared architectural principles from Amazon’s experience with large-scale systems — highlighting the importance of frugality, simplicity, and asynchronous patterns for building systems that last.
- Marcel Scherenberg of the financial services firm Stifel showcased how to use AI agents for provisioning Azure infrastructure through natural language prompts.
- Marc Müller of software developer Contentful showed how Optimistic UI updates can drastically improve Interaction to Next Paint (INP).
- David Rubin of Spotify offered insights into Spotify’s decade-long transformation, covering their shift from monoliths to microservices, from manual processes to AI-driven tooling.
- Markus Harrer of tech consultancy InnoQ introduced AI-driven software archeology — demonstrating how large language models and data analysis tools can help developers better understand, maintain, and evolve legacy systems.
Beyond the Code
Of course, the congress is not just about code — it is about people, too.
Outside the lecture halls, the official congress party provided an opportunity to unwind. During the event, our colleagues connected with tech enthusiasts such as Jost Kasparek, Vanessa Imhoff, and Linus Benkner — exchanging thoughts on the tech industry, reflecting on the conference sessions, and enjoying the atmosphere.
This event reminded us once more: while we come for the content, we stay for the community. A huge thank-you to the organizers for this world-class event — we returned full of ideas, inspiration, and energy for what is next.
