6 .NET API Anti-Patterns Sabotaging Your Performance and How to Swap Them
Modern .NET APIs are expected to handle thousands of requests per second with sub-100ms response times. Yet many teams unknowingly bake in anti-patterns that turn a well-architected system into a slow, resource-hungry mess. These patterns often start as shortcuts: a quick endpoint to return everything, a synchronous call in an async method, or a database query that grows with every feature request. Over time, they compound, and performance degrades until users notice. This guide identifies six of the most damaging anti-patterns we've seen in .NET APIs, explains the mechanics behind the slowdown, and offers direct replacements. The goal is not just to list problems, but to give you concrete steps to fix them—starting with your next sprint. 1. The Chatty API: Too Many Round Trips One of the most common performance killers is an API that forces clients to make multiple calls to assemble a single view.