Turn Old into New - Moving to Elixir Feature by Feature

Learn how to migrate legacy software systems to Elixir through incremental, feature-by-feature modernization in this conference talk from ElixirConf EU 2025. Discover practical strategies for transitioning from outdated technology stacks to modern Elixir applications while maintaining business continuity and user experience. Explore real-world challenges including inter-system communication between old and new architectures, adapting to functional programming paradigms, integrating existing data with Ecto, building system bridges, managing traffic shifts, and ensuring seamless user experiences throughout the migration process. Examine a concrete case study demonstrating the strangler fig pattern implementation, showing how an "ugly duckling" feature transformed into a modern, efficient solution. Gain insights into balancing long-term technical goals with day-to-day business requirements, implementing small incremental changes, and applying modern software engineering practices during large-scale system migrations.