Developing software for complex & ever-changing business domains is challenging enough, but factor in the need to integrate with multiple legacy systems while working closely with business experts & it can feel a little overwhelming. In EventStorming developers & business experts use sticky notes to map out a story of how the software system behaves given a particular business problem to solve. This improves communication & collaboration, uncovers misunderstandings early, & accelerates deeper domain knowledge. Learn EventStorming rules, how to facilitate an EventStorming workshop, how it can help a team cultivate shared understanding & be more productive, & how it transitions to designing loosely-coupled, distributed, event-based systems.

1. COLLABORATIVE LEARNING
FOR COMPLEX DOMAINS
EVENTSTORMING
@thepaulrayner
Paul Rayner

2. THE LANDSCAPE
Complex business rules &
processes
Knowledge silos
Numerous diverse (& often
legacy) system interactions

3. THE CRITICAL COMPLEXITY OF MOST
SOFTWARE PROJECTS IS IN
UNDERSTANDING THE DOMAIN
ITSELF
Eric Evans

4. HTTPS://EN.WIKIPEDIA.ORG/WIKI/ROSETTA_STONE#/MEDIA/FILE:ROSETTA_STONE.JPG

5. OPTIMIZE FOR
SHARED LEARNING

6. OPTIMIZE FOR
DISCOVERY

7. OPTIMIZE FOR
DESIGN

8. FOCUS ON
BEHAVIOR

9. leanpub.com/introducing_eventstorming

10. PLACE EVENTS ON
A TIMELINE

11. leanpub.com/introducing_eventstorming

12. WHAT IS A DOMAIN EVENT?
Something that happened
in the business
that your domain experts
care about

13. leanpub.com/introducing_eventstorming

14. SPECIES OF DOMAIN EVENTS
• A step in a business process
e.g. customer order submitted, customer paid $100, order
completed, item shipped.
• Something that happens on a scheduled basis
e.g. nightly account reconciliation completed, end of month.
• Something meaningful that occurs as a
result of something else happening
e.g. customer account locked after invalid password
entered 3 times

15. VISUALIZE
LEARNING
OPPORTUNITIES

17. leanpub.com/introducing_eventstorming

18. leanpub.com/introducing_eventstorming

19. EVENTS &
QUESTIONS FIRST

22. INVITE THE RIGHT
PEOPLE

23. Development team members and business people
gather in a room and together we create a visual map
of the flow of events

24. EVENTSTORMING
IN ACTION

28. PROVIDE UNLIMITED
MODELING SPACE

31. leanpub.com/introducing_eventstorming

32. leanpub.com/introducing_eventstorming

33. They lived
happily ever
after
Once
upon a
time… More modeling space than you expect

34. VISUALIZE
INTERACTIONS

35. leanpub.com/introducing_eventstorming

36. leanpub.com/introducing_eventstorming

37. VISUALIZE
BUSINESS RULES

38. leanpub.com/introducing_eventstorming

39. leanpub.com/introducing_eventstorming

40. EVENTSTORMING
A LEGACY APPLICATION

43. PROVIDE A
VISIBLE LEGEND

46. Sourced from leanpub.com/introducing_eventstorming

47. VISUALIZE
ALTERNATE FLOWS

48. Decided to Reimburse (alternate flow)
Decided to Repair (main flow)

49. NATURAL TRANSITION TO
DISTRIBUTED SYSTEMS

50. Event Stream
…
ECommerce Context
Event Stream
…
Order Management
Context

51. FACILITATION TIPS

52. EVENTSTORMING FACILITATION TIP #1
Focus first on
learning and
understanding

53. CLARIFYING QUESTIONS
‣ “What circumstances would cause ... to
happen?”
‣ “What was the path that led us here?”
‣ “What is a good example of …?”

54. CLARIFYING QUESTIONS
‣ "What do you mean by …?"
‣ "What might lead someone to do/need …?”
‣ "What else might happen…?

55. EVENTSTORMING FACILITATION TIP #2
Anchor to a
concrete business
example

56. EVENTSTORMING FACILITATION TIP #3
Clarify fuzzy
concepts and
language

57. Command is “Open Claim”
What should associated
event be called?

58. EVENTSTORMING FACILITATION TIP #5
Conversations
and examples are
primary

59. EVENTSTORMING FACILITATION TIP #6
Post first,
Ask questions
later

60. EVENTSTORMING FACILITATION TIP #4
Timebox

62. POSSIBLE LIMITATIONS
‣ Simple business domains (e.g. CRUD)
and/or systems
‣ Distributed teams
‣ Larger group/greater complexity =
better facilitation
‣ ???

63. WHY
EVENTSTORMING?

65. WHY EVENTSTORMING?
Collaborative learning
Cultivate mutual shared
understanding
Uncover misunderstandings & missing
concepts
Avoid rework

66. WHY EVENTSTORMING?
Model & explore complex
domains
Visual, tactile representation of system
behaviour & outcomes
Smoother transition to a rich domain
model, design and coding

67. QUESTIONS?
@thepaulrayner
Paul Rayner

68. THANKS!
@thepaulrayner
Paul Rayner

69. Sourced from leanpub.com/introducing_eventstorming