EventStorming: Benefits, Limits, and Practice

Suggesting an EventStorming workshop usually raises a fair question: why put a large group around a board instead of holding a regular process discussion? The answer depends on the goal, the participants, and the quality of facilitation. Here is where the method helps, where it has limits, and how to set up a useful session.

What EventStorming is in 30 seconds

EventStorming is a collaborative domain-exploration technique introduced by Alberto Brandolini. Participants place meaningful domain events on a physical or virtual board, usually in chronological order and phrased in the past tense: “Order placed,” “Payment confirmed,” “Item reserved.” That is enough to start exposing the flow and its ambiguities.

Commands, policies, external systems, people, and aggregates can be added when the purpose of the workshop calls for them. A Big Picture session needs breadth; Process Modelling explores a specific flow, while Software Design addresses software behaviour and component boundaries. Loading every notation onto the board at the start often gets in the way.

Benefits in practice

1. A shared view of the domain. Business experts, analysts, engineers, and adjacent teams can inspect the same process and align their vocabulary. The visual model also brings out knowledge that previously lived with only one or two people.

2. Earlier discovery of gaps and conflicts. A sequence of events makes missing branches, ambiguous states, manual steps, and competing interpretations easier to spot. Those questions are cheaper to resolve before implementation than after release.

3. More concrete discussion. Participants can point to a specific part of the flow, test assumptions, and record questions instead of debating several invisible mental models at once.

4. Broader participation. Building the model together gives different roles a way to contribute rather than merely comment on a finished diagram. This matters when a process crosses several departments or systems.

Where the pain begins

1. Time cost. A workshop can take anywhere from a couple of hours to a full day and may involve expensive specialists. That investment makes sense only when the team knows which question it is trying to answer and what outcome it needs.

2. The risk of getting lost in detail. A discussion can drift into naming events or designing individual services. Pick the level of detail in advance: establish the broad flow first, then explore only the areas that matter most.

3. Facilitation matters. The facilitator manages pace, brings the group back to the goal, makes room for different voices, and moves side topics into a parking lot. This is especially important when participants have very different levels of authority or expertise.

4. The illusion of completeness. The board captures the participants’ understanding at a point in time. It does not automatically become a specification or a source of truth. Decisions, boundaries, and open questions still need to move into the team’s working artifacts.

How not to blow the session

1. Define the question and choose the format: Big Picture for the domain, Process Modelling for a specific flow, or Software Design for the software model.
2. Invite people who understand different parts of the process and can clarify business rules, data, integrations, and constraints.
3. Appoint a facilitator, set a timebox, and agree on what is outside the session’s scope.
4. Start with domain events. Add other elements only when they help answer the workshop’s question.
5. End with a list of decisions, gaps, assumptions, owners, and next steps.
6. Decide what should be transferred into specifications, the backlog, diagrams, or architecture decision records. The board itself may remain a temporary discovery artifact.

What the team should take away

EventStorming works best when a team needs to explore a complex domain together and align on how a process behaves. Its value comes from the questions, the mix of participants, and the follow-up—not from the number of sticky notes on the wall.

The EventStorming website introduces the approach; Avanscoperta, the creator’s team, explains the three workshop formats.

Example: the order is paid, but stock is gone

An illustrative shop starts with a tidy sequence: order created, payment received, order shipped. Then a warehouse specialist asks when the last item is reserved.

The reservation may expire before payment confirmation. Add “reservation expired” and “payment received after reservation expiry.” Establish who decides between a new reservation, substitution and refund. Agree on the rule before drawing a new microservice.

Useful outputs include:

• the main sequence and exception path;
• an owner for the late-payment decision;
• a question about payment delays and retries;
• a test scenario with two requests for the final item;
• an owned follow-up if the business rule remains undecided.

A photograph of the board is not enough. Each consequential ambiguity needs an owner and a verifiable next step.

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Originally published on my Telegram channel @it_underside.

Yours, DPUPP