Reference
BPMN symbols — the complete reference
BPMN 2.0 defines a precise visual vocabulary. Every shape means something specific, and a diagram that uses the right shapes can be read unambiguously by analysts, developers, and workflow engines alike. This page covers the full symbol set, grouped the way you use it. Try any of them in the free BPMN editor — no signup, files stay on your device.
Events — circles: something happens
Events mark points where something happens rather than something being done. The border tells you the position: thin = start, double = intermediate, thick = end. The icon inside tells you the trigger.
Start event
Where the process begins. A plain (none) start means it is started manually or by a parent process. Every executable process needs one.
End event
Where a path finishes. A process may have several — one per distinct outcome ("Approved", "Rejected") is good practice.
Intermediate event
Something that happens mid-process: the process throws it (sends) or catches it (waits). The double border distinguishes it from start and end.
Timer event
A clock trigger: start a process every Monday, wait three days, or escalate when a deadline passes (as a boundary event on a task).
Message event
Communication crossing a pool boundary: an order arrives, a confirmation is sent. Message start events are how most service processes begin.
Terminate end event
Ends the entire process instantly, including parallel branches still running. A plain end event only finishes its own path.
Boundary event
Attached to a task's edge: it watches for a timer, error, or message while the task runs. Interrupting (solid border) cancels the task; non-interrupting (dashed) runs alongside. Other triggers exist too: error, signal, escalation, conditional, and compensation.
Activities — rounded rectangles: work being done
Task
A single unit of work. The generic form is fine for sketching; the typed variants below make responsibility explicit.
User task
A person performs the work through some interface: approve a request, review a document, enter data.
Service task
A system does the work automatically: call an API, run a calculation, update a record. No human involved.
Script, manual, send, receive, business rule tasks
Further specializations: a script executed by the engine, work done physically outside any system, sending or awaiting a message, or evaluating a decision table. Use them when the distinction matters to your audience.
Subprocess
A process within a process. Collapsed (shown with the +) it keeps the parent readable; expanded it shows its internal steps. Event subprocesses handle events for their parent; call activities invoke a reusable process defined elsewhere; transactions group steps that must succeed or be compensated together.
Gateways — diamonds: the flow splits or joins
Exclusive gateway (XOR)
Exactly one outgoing path is taken, decided by conditions. Every outgoing flow needs a condition or the gateway needs a default path — the editor's validation flags this, because it is the single most common BPMN mistake.
Parallel gateway (AND)
All outgoing paths run at once; the matching join waits for all of them. Splits and joins should come in pairs — an unmatched split means branches never synchronize.
Inclusive gateway (OR)
Every path whose condition is true runs — one, some, or all. Useful for "notify everyone who applies" situations; harder to reason about than XOR and AND, so use sparingly.
Event-based gateway
The process waits and the first event that occurs picks the path: "whichever comes first — the reply or the three-day timeout." The complex gateway (asterisk) exists for merge behavior none of the others express; it is rarely needed.
Pools, lanes, and flows
Pool and lanes
A pool is one participant — a company, a system, a customer. Lanes divide a pool by role or department. Sequence flows may not cross pool boundaries; that is what message flows are for. A collapsed "black box" pool hides internals you don't control.
Sequence flow
The solid arrow: order of execution inside one pool. A diagonal slash marker makes it the default path out of a gateway.
Message flow
The dashed arrow with an open head: communication between pools. Inside a single pool it is invalid — the editor flags it.
Data object and data store
The document shape is data flowing through the process (an invoice, an application); the cylinder is persistent storage the process reads or writes. Connected with dotted associations, they document inputs and outputs without affecting flow.
Text annotation and group
The open bracket holds free-text notes; the rounded dashed rectangle groups related elements visually. Neither affects execution — they exist for readers.
Markers on activities
| Marker | Meaning |
|---|---|
| Circular arrow | Standard loop — the task repeats while a condition holds. |
| Three vertical bars | Multi-instance parallel — one instance per item, all at once (e.g. one approval per reviewer). |
| Three horizontal bars | Multi-instance sequential — one instance per item, one after another. |
| Rewind symbol | Compensation — the activity undoes completed work when a transaction is cancelled. |
| Tilde (~) | Ad-hoc subprocess — contained tasks run in any order, at the performers' discretion. |
The fastest way to learn the vocabulary is to use it: open the editor and drop these shapes onto the canvas, or start from the example processes. New to BPMN entirely? Start with the tutorial.