Designing and Testing API Boundaries in Elixir Applications

Software systems must evolve, but changing core API interfaces without breaking existing features is a constant challenge. This text-based course guides you through the process of refactoring and testing boundary layers in Elixir applications. You will learn how to design robust API boundaries, safely introduce new parameters, and write reliable tests to ensure system stability. What you'll learn: Understand the fundamental concept of boundary layers and API design in functional programming; Modify existing function signatures to accept new arguments without breaking compatibility; Apply pattern matching and multi-clause functions to handle evolving data structures; Configure mock behaviors and stubs using modern testing patterns to isolate dependencies; Write robust ExUnit integration tests to verify boundary interactions; Implement modern Elixir type specifications to document and validate your API contracts. The course starts with foundational definitions of boundary layers before moving into step-by-step refactoring patterns and testing strategies. You will read through clear, structured explanations and analyze practical code snippets to build your confidence. This course is designed for Elixir developers who understand basic syntax and want to master application architecture and testing. Start reading today to build more resilient and maintainable Elixir applications.