Software development relies heavily on reusable li- braries and software components. For correct use of the provided API, proper documentation is needed. API usage is often demonstrated by giving example applications and code samples. In this paper we propose an approach for mining such usage scenarios from run-time communication between sample applications and the API. This is done au- tomatically by first monitoring the API usage of sample ap- plications, then filtering the generated traces, and finally synthesizing the sequence diagrams and illustrating them in a well-formed way as UML2 sequence diagrams. Such usage scenarios support the software engineer in compre- hending the usage of the API. With proper tool support they can also be used for validating other applications? API us- age and for generating code for a new application using the same API.