# BPMN Diagram Types

**In short:** BPMN offers collaboration diagrams, which show pools and the messages between them, and conversation diagrams, which give a high-level view of what participants talk about. Choreography diagrams are a newer third type.

## Explanation

BPMN is a notation for drawing business processes. It has more than one diagram type. Each type shows a different level of detail.

**Collaboration diagram**

A collaboration shows pools and the message flows between them. A pool stands for a participant. A message flow is a line showing a message passing from one pool to another.

A pool can take one of three forms:

- It can be empty.
- It can be a black box. You see the participant but not its inner workings.
- It can be a white box. You see the process inside the pool.

In a public process, the partners' internal processes stay hidden as black boxes. Only the messages between the partners are visible.

**Conversation diagram**

A conversation diagram is a high-level view of communication. It leaves out the internal steps of each process. It answers one question: which communication topics exist between the participants?

Conversation links carry no order or timing. They are not sequence flows. A conversation diagram also does not show the order of messages. A collaboration diagram does show this. So the two types complement each other.

**Choreography diagram**

Choreography diagrams are new in BPMN 2.0. They focus on interactions and message flows between processes. Their focus is the messages between the participant pools.

**Choosing a type**

- Use a conversation diagram for an overview of which topics the participants discuss.
- Use a collaboration diagram when you need to see how messages flow between participants.
- Use a choreography diagram when the interaction between processes is the main subject.

## Example

A web shop works with a payment provider. A conversation diagram lists the topics the two talk about, such as payment. It shows no steps and no order. A collaboration diagram then draws the shop as a white-box pool with its process inside. It draws the payment provider as a black-box pool. A message flow connects them, so readers see the exchange without the provider's internals.

## Trade-offs

A conversation diagram is quick to read, but it hides sequence and timing. A collaboration diagram shows the message flow, but it needs more detail and takes more effort to draw. Black-box pools keep partner internals out of view. The cost is that readers cannot see what happens inside those partners.

BPMN diagram: [A collaboration: a black-box customer pool sends a message to a white-box shop pool that shows its process.](https://arc.fuet.ch/diagrams/concepts/modeling-bpmn/bpmn-diagram-types/diagram-1.bpmn)

## Checks

- A diagram meant as a topic overview omits internal process steps and does not imply message order.
- Where a collaboration diagram shows a partner's internals as hidden, that partner's pool is drawn as a black box.
- Where message order between participants matters, a collaboration diagram is used rather than a conversation diagram.

## Related

- [BPMN Collaboration Diagram](https://arc.fuet.ch/concepts/modeling-bpmn/bpmn-collaboration-diagram.md)
- [BPMN Conversation Diagram](https://arc.fuet.ch/concepts/modeling-bpmn/bpmn-conversation-diagram.md)
- [BPMN Swimlane (Pool and Lane)](https://arc.fuet.ch/concepts/modeling-bpmn/bpmn-swimlane-pool-and-lane.md)
- [BPMN 2.0 Notation](https://arc.fuet.ch/concepts/modeling-bpmn/bpmn-2-0-notation-overview.md)
- [Data Exchange between BPMN Processes](https://arc.fuet.ch/concepts/modeling-bpmn/data-exchange-between-bpmn-processes.md)
- [Levels of Process Modeling](https://arc.fuet.ch/concepts/modeling-bpmn/levels-of-process-modeling.md)
- [BPMN Modeling Guidelines](https://arc.fuet.ch/concepts/modeling-bpmn/bpmn-modeling-tips.md)
- [Runtime View](https://arc.fuet.ch/concepts/documentation/runtime-view.md)

## Sources

- [BPMN Orchestration vs Choreography vs Collaboration](https://www.visual-paradigm.com/guide/bpmn/bpmn-orchestration-vs-choreography-vs-collaboration/;WWWSESSIONID=EC70CA1EB8C6EE5DFB98B1231D2FED1A.www1) — visual-paradigm.com, accessed 2026-11-09
- [What Is a BPMN Conversation Diagram? | BPMN Guide](https://skills.visual-paradigm.com/docs/bpmn-diagram-types-explained/bpmn-conversation-diagram/bpmn-conversation-diagram/) — skills.visual-paradigm.com, accessed 2026-11-09