BPMN Collaboration Diagram: Customer, Shop and Courier
A collaboration diagram shows how separate organisations work together. Draw a customer pool, an online shop pool and a courier pool in the free bpmn.io modeler, and connect them with dashed message flows for one delivery.
Step by step
Three parties
- Collaboration diagram. One delivery involves 3 parties: the customer, the shop and the courier. A BPMN collaboration diagram shows how they communicate. This is the finished model we build in bpmn.io.
- New diagram. Start a new diagram in bpmn.io. It opens with a start event. Name it Gift needed.
Customer pool
- Customer pool. Drag a pool from the palette onto the canvas. The first pool wraps around the start event that is already there. Make it wide and name it Customer. Each party gets its own pool. From Gift needed, add the customer's first task, Place order. Then add a second task further to the right, Receive parcel. This is where the customer waits for the delivery. Finish the customer's side with an end event called Gift received.
Shop pool
- Shop pool. The shop is a separate company, so it gets its own pool. Drag a second pool in under Customer, make it the same width and name it Online Shop. The shop's work starts when an order comes in. Drag a start event into the Online Shop pool and name it Order received. Select it, click the wrench icon and search for message start to turn it into a message start event. The envelope shows that a message starts this process. Add the shop's task after it, Book courier. Then end the shop's side with an end event called Courier booked.
Courier pool
- Black box pool. The courier is a third company. We don't know its inside steps, and we don't need them. So drag in a thin pool, name it Courier and leave it empty. This is a black box pool.
Message flows
- Message flows. Now connect the pools. Drag the arrow tool from Place order onto Order received in the shop's pool. A line between pools is dashed, because it is a message flow. The shop sends the booking to the courier. Drag a message flow from Book courier onto the Courier pool. A black box pool takes messages on its edge. The courier brings the parcel, so drag a message flow from the Courier pool up to Receive parcel.
- The finished model. Click on an empty part of the canvas to see the whole delivery: 3 pools, solid sequence flows inside each pool, and dashed message flows between them.
Recap
- The rules. The rules: one pool per party. Sequence flows stay inside a pool. Message flows only go between pools. A party whose steps you don't model is an empty black box pool.
Common mistakes
- Using lanes for separate companies. Lanes are for roles inside one organisation, such as Sales and Warehouse. Separate organisations like the shop and the courier each need their own pool.
- Joining pools with a sequence flow. A solid sequence flow can't cross from one pool to another. Use a dashed message flow between pools, and keep sequence flows inside each pool.
- Guessing another company's inside steps. If you don't know or don't need the courier's process, leave its pool empty as a black box and connect message flows to the pool's edge.
- A plain start event for a process that waits for a message. The shop only starts when an order arrives, so make Order received a message start event and connect the message flow from Place order to it.
When a business analyst uses this
In a discovery workshop for an order-to-delivery process, a business analyst draws the customer, the shop and the courier as pools to agree what each party sends and receives. Each message flow, such as the courier booking, then becomes an interface or integration requirement to confirm before sign-off.
Questions people ask
What is a BPMN collaboration diagram?
It is a BPMN diagram with 2 or more pools, one per party, linked by message flows. It shows how separate organisations or systems work together, like a customer, a shop and a courier.
What is the difference between a BPMN process diagram and a collaboration diagram?
A process diagram shows the steps of one party's process. A collaboration diagram puts each party in its own pool and shows the messages that pass between them.
What is an example of a BPMN collaboration diagram?
An online order: the customer places an order, the shop receives it and books a courier, and the courier delivers the parcel back to the customer. Each party is a pool, and each hand-off is a dashed message flow.
