For someone not familiar with Feign: Feign is a declarative REST client. Meaning, it helps to write clients for REST APIs in concise and quite easy way. More info can be found here. Some time ago I have faced quite a weird and no-intuitive issue while using the client layer written using Spring Cloud wrapper around Feign. In this post I want to share the lesson learned with you. For the sake of simplicity I will demonstrate the issue using the one GET method client.