Note: View Sequence Diagram Best Practices to learn about sequence fragments.

Each object has a column and the messages exchanged between them are represented by arrows.Ī Quick Overview of the Various Parts of a Sequence Diagram Sequence Diagram NotationsĪ sequence diagram is structured in such a way that it represents a timeline which begins at the top and descends gradually to mark the sequence of interactions. In simpler words, a sequence diagram shows different parts of a system work in a ‘sequence’ to get something done. They illustrate how the different parts of a system interact with each other to carry out a function, and the order in which the interactions occur when a particular use case is executed. Sequence diagrams, commonly used by developers, model the interactions between objects in a single use case. Among the three, sequence diagrams are preferred by both developers and readers alike for their simplicity. These diagrams are used to illustrate interactions between parts within a system. There are 3 types of Interaction diagrams Sequence diagrams, communication diagrams, and timing diagrams. This sequence diagram tutorial is to help you understand sequence diagrams better to explain everything you need to know, from how to draw a sequence diagram to the common mistakes you should avoid when drawing one.

System sequence diagram online tool