Event Storming

A workshop technique for mapping a business domain using sticky notes.

The Technique

Gather the team with a long wall, sticky notes, and markers. Place events (things that happen, in past tense) along a timeline. Then layer in commands, actors, policies, and systems. The wall becomes a shared map of the domain.

What You Produce

A timeline of domain events in chronological order.
Commands and actors that trigger events.
Policies and reactions linking events.
Hotspots — places of disagreement or confusion.

Why It Matters

Reveals the real business flow, not the sanitised version.
Surfaces edge cases, exceptions, and gaps in understanding.
Aligns engineers, product, and domain experts on shared language.

When to Use

Before designing a new system.
When a team can't agree on how a process works.
When documentation disagrees with reality.

The Trap

Treating the output as a design instead of a discovery. Event storming finds the shape of the problem; design comes after.