Ktor on Virtual Threads vs Coroutines

--- title : " Ktor at 50K Connections: Coroutines vs Virtual Threads on a $20 VPS" published : true description : " A hands-on walkthrough benchmarking Ktor coroutines against JVM virtual threads at 50K concurrent connections — and why a single VPS beats Kubernetes for early-stage startups." tags : kotlin, architecture, performance, cloud canonical_url : https://blog.mvpfactory.co/ktor-50k-connections-coroutines-vs-virtual-threads --- ## What You Will Learn In this workshop, we will benchmark two high-concurrency models available in Ktor — **Kotlin coroutines** and **JDK 21 virtual threads (Project Loom)** — serving 50K concurrent connections on a single 4-core VPS. By the end, you will have a working Ktor configuration, understand the memory and concurrency tradeoffs between both models, and know exactly when a $20 VPS stops being enough. Let me show you a pattern I use in every project that saves real money at the early stage. ## Prerequisites - JDK 21+ installed - Ktor 2.3.x project