BPMN Cheat Sheet
Every commonly used BPMN 2.0 symbol: what it means, when to reach for it, and the mistake that most often makes diagrams invalid, with clause references to the OMG 2.0.2 specification throughout.
Events
Circles. Something that happens: a trigger, a milestone, an outcome. Border weight tells you which kind.
Start event
Where the process begins: an order arrives, a form is submitted, a timer fires. Thin single border.
Common mistake: Giving a start event an incoming sequence flow. The spec forbids it, and conditions on flows out of a start event are also invalid.
BPMN 2.0.2 §10.5.2, p.244
End event
Where a path terminates and its token is consumed. Thick single border. Name it after the outcome: "Order shipped", not "End".
Common mistake: Leaving paths that never reach an end event, or drawing flows out of one. Every start needs a reachable end.
BPMN 2.0.2 §10.5.3, p.246
Intermediate event
Something that happens mid-process: waiting for a reply, a deadline, a signal. Double thin border, placed in the flow.
Common mistake: Dangling it off to the side. An intermediate event in the normal flow needs both an incoming and an outgoing sequence flow.
BPMN 2.0.2 §10.5.4, p.249
Message event
A message arrives (catch) or is sent (throw). The envelope marker on any event circle.
Common mistake: Connecting message flows to elements inside the same pool. Messages only travel between pools.
BPMN 2.0.2 §9.4, p.120
Timer event
A deadline, delay, or schedule: "wait 3 days", "every Monday". The clock marker; catch-only.
Common mistake: Using a timer as a throw event. Timers can only catch (wait for) time, never throw it.
Activities
Rounded rectangles. Work being done. Name them verb + noun: "Approve invoice", not "Invoice approval".
Task
A single unit of work that is not broken down further. The default when no specific type fits.
Common mistake: Leaving tasks unnamed, or naming them as states ("Approved") instead of actions ("Approve invoice").
User task
Work a person performs through a system: approving a request, filling a form. The person marker, top-left.
Common mistake: Using user tasks for fully automated steps. That misleads anyone estimating manual effort from the diagram.
Service task
Work a system performs automatically: calling an API, running a calculation, sending to a queue. The gear marker.
Common mistake: Modeling every step a system touches as a service task. If a human drives it, it is a user task.
Sub-process
A compound activity that expands into its own flow. The [+] marker. Use it to keep the parent diagram readable.
Common mistake: Nesting so deep that no single level tells the story. Two levels is usually the ceiling for readability.
Gateways
Diamonds. They route tokens; they never do work. A gateway either splits one path into several or merges several into one, not both at once.
Exclusive gateway (XOR)
Pick exactly one outgoing path. Phrase the name as a question ("In stock?") and label every branch, or mark one as the default.
Common mistake: Unlabeled branches with no default flow. Readers cannot tell which path fires, and the spec requires conditions or a default.
BPMN 2.0.2 §10.6.2, p.290
Parallel gateway (AND)
Fire all outgoing paths at once, and later wait for all incoming paths at the join. The + marker.
Common mistake: Putting conditions on parallel branches (invalid: all paths always fire), or forgetting the join so tokens never synchronise.
BPMN 2.0.2 §8.4.13, p.97
Inclusive gateway (OR)
Fire one or more paths depending on conditions: "email, SMS, or both". The O marker.
Common mistake: Reaching for OR when XOR or AND fits. Inclusive joins have the most complex semantics in BPMN and most engines handle them poorly.
BPMN 2.0.2 §10.6.3, p.292
Event-based gateway
The process waits, and whichever event happens first wins: "reply received or 7 days pass". The pentagon-in-circle marker.
Common mistake: Routing it to tasks or other gateways. Its targets must be catching intermediate events or receive tasks.
BPMN 2.0.2 §10.6.6, p.297
Connections
Two kinds of line, two different meanings, and they are not interchangeable.
Sequence flow
Solid line, filled arrowhead: the order of work inside one pool. This is what tokens travel along.
Common mistake: Crossing a pool boundary with a sequence flow. The spec forbids it. Use a message flow between pools.
BPMN 2.0.2 §8.4.13, p.97
Message flow
Dashed line, open circle start, open arrowhead: communication between pools: an order sent, an invoice returned.
Common mistake: Drawing message flows inside a single pool, or connecting them to gateways (they may only touch pools, activities, and message events).
BPMN 2.0.2 §9.4, p.120
Pools and lanes
The containers that give BPMN its famous swimlane look.
Pool and lanes
A pool is one participant: your company, the customer, a supplier. Lanes divide a pool by role or department. All sequence flows stay inside the pool; pools talk to each other only via message flows.
Common mistake: Making every department its own pool. If they share one end-to-end process, they are lanes in one pool. Separate pools imply separate processes coordinating by messages.
BPMN 2.0.2 §9.3
Frequently asked questions
What is the difference between BPMN and a flowchart?
BPMN is a standardised notation (OMG BPMN 2.0.2) with precise execution semantics: symbols have defined meanings, files exchange between tools as .bpmn XML, and rules like token flow make diagrams unambiguous enough for automation engines to run. A flowchart is freeform: fine for a sketch, but two readers can interpret it two ways.
Which BPMN symbols should I learn first?
Five cover most real diagrams: start and end events, the task, the exclusive gateway, and sequence flows. Add pools and lanes when more than one role is involved, and parallel gateways when work genuinely happens simultaneously. Everything else can wait.
How do I check whether my diagram follows these rules?
Use the free BPMN validator on this site: upload a .bpmn file and it checks 19 normative rules from the 2.0.2 spec (including every rule referenced on this page) with the exact clause cited for each failure.
What does BPMN 2.0.2 mean, and is there a newer version?
BPMN 2.0 is the standard published by the OMG; 2.0.2 (formal/2013-12-09) is its current maintenance release and remains the version every major tool implements. There is no BPMN 3.0.
Stop drawing symbols by hand
Describe the process in plain text (or paste the meeting transcript) and Swimdraft produces a diagram that follows every rule on this page, checked against the spec automatically.
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