Systems, methods, and computer program products to perform an operation comprising non-blocking runtime debugging of an application executing in a single threaded server environment by obtaining a first request from a head of a request queue, processing the first request based on server application code under debugging, triggering, in response to the first request, a debugging procedure, pausing processing of the first request based on the debugging procedure, tagging the first request with an indication that the first request is in debugging, placing the first request back on the request queue in a position behind the head of the queue, storing debug information related to the first request, and executing at least a second request from the request queue while processing of the first request is paused.