BPMN notation reference

BPMN has a large vocabulary and a small core. This is the reference for the whole thing: what each symbol means, and the rules about which may connect to which.

If you are learning it, read events, gateways and flows first. Those three cover most real models.


#When it matters

  • Reading a BPMN model somebody else drew.

  • Reviewing a model that will be executed, where notation is behaviour.

  • Settling an argument about whether a line should be dashed.


#The symbols

Symbol

Means

Events

Circles. Something happens: start, timer, message, error, end.

Activities

Rounded rectangles. Work, done by a person or a system.

Gateways

Diamonds. The path splits or joins.

Flows

Solid within a pool, dashed between pools.

Swimlanes

Pools for participants, lanes for roles.

Artifacts

Data objects, stores, groups and annotations.


#A few things that catch people out

  • The rule that catches everyone: sequence flow never crosses a pool boundary.

  • Marker icons are semantics, not decoration. A service task and a user task behave differently.

  • A model you cannot explain without annotations is usually over-modelled.



The notation is the meaning.