HTTP Verb OPTIONS requires to have Accept header defined, response should provide some guidance about this ---------------------------------------------------------------------------------------------------------- Key: WFWIP-151 URL: https://issues.jboss.org/browse/WFWIP-151 Project: WildFly WIP Issue Type: Enhancement Components: MP Metrics Reporter: Rostislav Svoboda Assignee: Jeff Mesnil Priority: Major HTTP Verb OPTIONS requires to have Accept header defined {code} $ curl -X OPTIONS http://127.0.0.1:10090/metrics/vendor No exporter found for method OPTIONS and media type {code} I have to specify json mediatype {code} curl -X OPTIONS -H "Accept: application/json" http://127.0.0.1:10090/metrics/vendor {code} I was expecting that I get -the json response or at least more- helpful message. OpenLiberty returns {code} Error 406: CWMMC0000I: The accept header format */* is incorrect. {code} which at least points user to define proper header Update: Spec requires header to be defined, so WF could be a bit more helpful in the response message {code} The implementation must return a 406 response code if the request’s HTTP Accept header for an OPTIONS request does not match application/json. {code}