EventStorming - Collaborative Learning for Complex Domains • Paul Rayner • YOW! 2016

EventStorming is a collaborative modeling technique focused on behavior and outcomes rather than structure and form, using different colored sticky notes on a timeline to map business processes

Core elements include:

• Orange stickies for domain events (things that happened)
• Blue stickies for commands (user actions)
• Yellow stickies for personas/users
• Pink stickies for questions/unknowns
• Green stickies for read models/data views
• Purple/lilac stickies for policies/business rules

The technique helps bridge the gap between technical and business teams by focusing on a shared understanding of the domain through events rather than technical implementation details

Key patterns for events include:

• Steps in business processes
• Time-based/scheduled events
• External system triggers
• Commands leading to events
• Events triggering other events

Best practices for facilitation:

• Start with unlimited modeling space
• Focus on exploration over decision-making
• Post first, ask questions later
• Use concrete examples
• Timeboxing and regular breaks
• Have the right domain experts in the room

Particularly valuable for:

• Complex business domains
• Legacy system understanding
• Integration projects
• Large distributed systems
• Innovation work alongside existing systems

The process follows divergent thinking (getting ideas out) followed by convergent thinking (focusing on key areas and next steps)

Pink stickies (questions/uncertainties) help identify knowledge gaps and needed follow-up actions, making it clear when more research or expertise is needed

The collaborative nature creates higher engagement and understanding than traditional technical modeling approaches

The technique succeeds by making implicit knowledge explicit and creating a shared visual language between technical and business stakeholders