Lesson 1 of 4
Events are circles
Events are represented by circles. The border weight tells you what type they are:
| Border style | Event type | Meaning |
|---|---|---|
| Thin border | Start Event | Something triggers the start of the process |
| Double border | Intermediate Event | Something occurs during the process — may pause, redirect, or signal |
| Thick border | End Event | The process reaches a conclusion — a defined outcome |
The plain-English rule
If it starts the process → Start Event. If it finishes the process → End Event. If it happens in the middle and changes what the process does next → Intermediate Event.
Event markers: what goes inside the circle
A blank circle is a 'None' event — the simplest form, used when no specific trigger or result needs to be named. When the trigger or result has a specific type, an icon is placed inside:
| Marker icon | Type | Start Event use | Intermediate use | End Event use |
|---|---|---|---|---|
| Envelope | Message | Process triggered by receiving a message (e.g. supplier sends invoice) | Process waits for a message (Catch) or sends one (Throw) | Process ends by sending a message (e.g. confirmation email) |
| Clock | Timer | Process starts at a scheduled time (e.g. end-of-month batch) | Process waits for a time period before continuing | Not typically used as End Event |
| Lightning bolt | Error | Not used as Start (except in Event Subprocesses) | Process catches an error thrown by a system task | Process ends in an error state |
| None (blank) | None / Plain | Process starts — no specific trigger to name | Not commonly used | Process ends — primary outcome |
Common mistake
Using a Task called 'Receive Customer Order' or 'Receive Invoice' when the receipt is what starts the process. Receiving a communication from an external participant is a Message Start Event, not a task. Receiving a trigger is not the same as performing work.
Multiple End Events
A process can and should have multiple End Events when there are distinct outcomes. An invoice approval process has at least two: Invoice Paid and Invoice Rejected. Name each End Event with its business outcome — not generically as 'End.'
✓ When to use
- Message Start Event when your process is triggered by a communication from an external party
- Timer Start Event when a process runs on a schedule
- Multiple, named End Events when the process has genuinely distinct outcomes
✗ When not to use
- ✕Don't use an Intermediate Event just to annotate time passing — only when it actually changes the flow
- ✕Don't name End Events generically as 'End' — name them with their business outcome
- ✕Don't use a Task to represent a trigger — if something arriving starts the process, it is a Start Event