All participants write Domain Events (orange, past tense) in parallel and place them roughly in chronological order on the wall. No sorting, no discussion.
Facilitation hint
Expect 80-300 events. If only 30 events are present after 20 min, domain knowledge is missing or the question is too narrow. No one corrects things in this phase.
What needs to be finished first
A list of domain experts by business area is available, so the right people can evidence the full flow.
In very complex domains, at least one narrative example story with actors and artifacts is available so the event chain can be attached to it.
What needs to be ready before start
Large wall or digital board with at least 8 m of horizontal space; orange sticky notes (Events), blue (Commands), yellow (Actors), pink (Hot Spots), purple (Policies), green (Read Models); markers; camera for snapshots; parking-lot area.
A facilitator with EventStorming experience; three to six domain experts from business; two to four engineers or architects; one scribe for hot spots and open questions.
Clearly bounded business flow (e.g. "from order entry to fulfillment"); glossary of known domain terms; existing process documentation as backup, not as template.
2-8 h
Mark wall with timeline (left start, right end). Make the color legend visible. State the rule: Events are in past tense and business-relevant. Phones away, no laptops except for the scribe.
The one question this method answers
Which business events, triggers, and boundaries shape the flow, and where do friction, risk, or learning needs arise?
Marker: Phase
| Step | Duration | Action | Hint |
|---|---|---|---|
1Phase 1: Chaotic Storming | 30-60 min | All participants write Domain Events (orange, past tense) in parallel and place them roughly in chronological order on the wall. No sorting, no discussion. | Expect 80-300 events. If only 30 events are present after 20 min, domain knowledge is missing or the question is too narrow. No one corrects things in this phase. |
2Phase 2: Timeline Enforcement | 30-45 min | Order events chronologically, consolidate duplicates, mark gaps. Highlight pivotal events (turning points), for example by moving them upward. | Disagreement about order is useful, not a disruption. If the group cannot agree, place both variants and mark them as a Hot Spot. |
3Phase 3: Commands, Actors, Policies | 45-90 min | Place the triggering command (blue) and Actor (yellow) in front of each event. Mark automatic follow-up reactions as Policies (purple). Add Read Models (green) where decisions need data. | If no command fits in front of an event, it is either an external trigger (system, time) or a gap. Make both explicit. |
4Phase 4: Hot Spots and Boundaries | 30-45 min | Use pink for each point of friction, risk, uncertainty, or conflict. Then draw boundaries (dashed lines) for bounded contexts or organizational boundaries. | Hot Spots are the most valuable output, not a lack. If none appear, the facilitator should explicitly ask for workarounds, escalations, and exceptions. |
5Phase 5: Follow-ups and Outputs | 20-30 min | Photograph the wall at each phase. Name one owner and next action per Hot Spot. Derive glossary terms from events and include them in the Ubiquitous Language. | Without named follow-ups, energy dissipates. At least three Hot Spots need owner and date before the workshop ends. |
What comes out at the end
Photo documentation of the wall per phase plus structured markdown with linear event timeline, Hot Spot list with owner and date, bounded context sketch, and glossary of domain terms.
One folder per workshop with date, participant list, and phase snapshots. For follow-up workshops, do not overwrite but create a new version and document the delta.
Compact working template for Event Storming with context, input, output artifacts, and next step.
Rapid, visual domain exploration through Business Events, Commands, Policies, and Actors on a timeline.
When and for what do we use this method?
Which data, observations, decisions, or materials are available?
Short notes along the runsheet.
Owner, date, and success signal.
Concrete filled scenario, fictional example
Concrete filled scenario, fictional example
Participants: 4 domain experts (Sales, Warehouse, Shipping, Customer Service), 3 engineers, 1 architect.
Pivotal Events: OrderPlaced, PaymentAuthorized, OrderShipped, OrderDelivered.
Timeline excerpt (151 events total):
Hot Spots:
Bounded Contexts (proposal): Ordering, Payment, Inventory, Shipping, Returns. The Ordering → Payment interface is the hottest conflict.
Recognize symptoms and steer against them
Notes say "Order" or "Shipping" instead of "OrderPlaced" or "ShippingStarted."
Post a good example on the wall before phase 1. If a wrong form appears, correct it immediately. Wrong notation spreads quickly.
The discussion shifts to "how we would build it" instead of what happens.
Use a visible parking lot for solution ideas. The facilitator interrupts immediately and parks the topic. Return to phase 5 only if relevant.
Only engineers present, all events are technical (DatabaseUpdated, MessagePublished).
Cancel or postpone the workshop. EventStorming without business voices creates a data model, not a domain model.
Events overlap, order becomes unreadable, new notes push old ones out.
Plan at least 8 m. If not possible, split the flow into two workshops (for example Sales side and fulfillment side). In digital setups, zooming in helps but harms overview.
Pink notes are everywhere, but none has owner or date.
Reserve the last 20 min specifically for follow-up assignment. Do not end the workshop before at least three Hot Spots have owner and deadline.
Done signals checkable in under a minute
Go to the profile for purpose, similar methods, and sources or continue to the next method in the catalog.