Spring MVC vs WebFlux in 2025: Which One Should You Actually Use?

Spring MVC and Spring WebFlux solve the same problem — handling HTTP requests — but through completely different concurrency models. With Spring Boot 4 and Java 25 both shipping in late 2025, the landscape has shifted significantly. Let me walk through every dimension that matters for making the right architectural decision. Table of Contents 1. Programming model: imperative vs reactive 2. Framework internals: what's actually different under the hood 3. Cross-cutting concerns compared 4. Context propagation & ThreadLocal 5. Transactions & persistence 6. Java 25 + Spring Boot 4: do we still need WebFlux? 7. Decision guide 1. Programming model: imperative vs reactive The most visible difference between Spring MVC and Spring WebFlux isn't in the framework itself — it's in how you write code: Spring MVC uses the familiar thread-per-request imperative model. WebFlux uses reactive streams via Project Reactor , where every value is wrapped in a Mono<T> (zero or one result) or Flux<T> (zero to