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Might & Magic of Domain-Driven Design — Mateusz Nowak at wroclove.rb 2025

Mateusz Nowak's wroclove.rb 2025 talk uses Heroes of Might & Magic III as a running analogy to present an application design process built on Domain-Driven Design, EventStorming, Event Modeling, and the decider/automation patterns. He argues that battles for software quality are won during whiteboard planning and modeling experiments — making code review a formality and enabling modular systems where developers become real business partners.

Model

claude-opus-4-7

Ingestion

02f504a3

Input tokens

172,281

fresh: 84,936
cached: 73,965
cache write: 13,380

Output tokens

10,977

Duration

169.0s

Roundtrips

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Cost

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Nodes/edges extracted

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Read set (nodes/edges)

87 / 2

Nodes (19)

update Mateusz Nowak person

attrs (empty) → {"blog" => "DDD Heroes (English) + Polish blog", "location" => "Poland (Wrocław area)", "experience_years" => "8"}

description Conference speaker. → Polish developer and technical leader from Bratislava-area / Wrocław region with eight years of industry experience a...

short_description Conference speaker. → Backend/full-stack developer and speaker working on event sourcing with AxonIQ.

create Vertical Slice concept

kind (empty) → concept

name (empty) → Vertical Slice

slug (empty) → vertical-slice

attrs (empty) → {"category" => "practice"}

description (empty) → Vertical division of an Event Model into independently implementable units. Three slice types: write slice (command t...

short_description (empty) → Unit of work in Event Modeling: write, read, or automation slice bounded by events.

create DDD Heroes Blog resource

kind (empty) → resource

name (empty) → DDD Heroes Blog

slug (empty) → ddd-heroes-blog

attrs (empty) → {"type" => "blog-post", "author" => "Mateusz Nowak"}

description (empty) → English-language blog authored by Mateusz Nowak covering DDD, Event Modeling, event sourcing, the decider pattern and...

short_description (empty) → Mateusz Nowak's English blog about DDD, Event Modeling and event sourcing.

update Might & Magic of Domain-Driven Design talk

attrs {"type" => "talk"} → {"date" => "2025-03-14", "type" => "talk", "code_language" => "Ruby", "example_domain" => "Heroes of Might and Magic ...

description Talk at wroclove.rb 2025. → Mateusz Nowak's wroclove.rb 2025 single-speaker talk. Frames DDD as 'might' (patterns/heuristics learned from books a...

short_description Talk at wroclove.rb 2025. → Mateusz Nowak's wroclove.rb 2025 talk on DDD, Event Modeling, and modular design via a Heroes 3 example.

create AxonIQ company

kind (empty) → company

name (empty) → AxonIQ

slug (empty) → axoniq

attrs (empty) → {"industry" => "event sourcing frameworks / software"}

description (empty) → Company responsible for the Axon Framework. Its mission, as described by Mateusz Nowak (contractor at AxonIQ), is to ...

short_description (empty) → Company behind Axon Framework; mission to make event sourcing easy in the Java world.

create Axon Framework tool

kind (empty) → tool

name (empty) → Axon Framework

slug (empty) → axon-framework

attrs (empty) → {"category" => "framework", "language" => "Java"}

description (empty) → Framework for event sourcing maintained by AxonIQ. Used daily by Mateusz Nowak in his client work alongside DDD, Even...

short_description (empty) → Java framework for event sourcing, CQRS and DDD built by AxonIQ.

create Event Modeling concept

kind (empty) → concept

name (empty) → Event Modeling

slug (empty) → event-modeling

attrs (empty) → {"category" => "practice", "coined_at" => "EventStorming Summit 2018", "coined_by" => "Adam Dymitruk", "former_name" ...

description (empty) → Modeling technique coined by Adam Dymitruk in 2018 at the EventStorming Summit, originally called 'single flow event ...

short_description (empty) → Modeling technique that describes business processes as sequenced frames of commands, events and views.

create Adam Dymitruk person

kind (empty) → person

name (empty) → Adam Dymitruk

slug (empty) → adam-dymitruk

description (empty) → Coined Event Modeling in 2018 at the EventStorming Summit. Initially called his method 'single flow event storming'.

short_description (empty) → Originator of Event Modeling (2018).

create Decider Pattern concept

kind (empty) → concept

name (empty) → Decider Pattern

slug (empty) → decider-pattern

attrs (empty) → {"category" => "pattern"}

description (empty) → Functional domain-logic pattern Mateusz Nowak uses to implement Event-Modeled systems. Three pure functions compose t...

short_description (empty) → Persistence-agnostic functional pattern with decide, evolve and react pure functions.

create Automation Pattern concept

kind (empty) → concept

name (empty) → Automation Pattern

slug (empty) → automation-pattern

attrs (empty) → {"category" => "pattern"}

description (empty) → Event Modeling building block (the 'automation slice') that acts as a process orchestrator between autonomous modules...

short_description (empty) → Event Modeling building block: a robot that reacts to events by dispatching commands across modules.

create Model Domain By Reverse-Engineering Apps You Use takeaway

kind (empty) → takeaway

name (empty) → Model Domain By Reverse-Engineering Apps You Use

slug (empty) → model-domain-by-reverse-engineering-apps-you-use

attrs (empty) → {"type" => "recommendation"}

description (empty) → Practical exercise to gain DDD experience when you don't have an Eric Evans at work. Step 1: model a domain you use d...

short_description (empty) → Train DDD intuition by modeling Uber/e-commerce domains and their new features.

create Use Whiteboard Experiments To Find Module Boundaries takeaway

kind (empty) → takeaway

name (empty) → Use Whiteboard Experiments To Find Module Boundaries

slug (empty) → use-whiteboard-experiments-to-find-module-boundaries

attrs (empty) → {"type" => "insight"}

description (empty) → Heuristic presented in the talk: to verify whether a set of events belongs to one module, ask 'what happens after thi...

short_description (empty) → Ask what happened before/after each event to discover autonomous module boundaries.

create Replace Code Review With Architecture Execution takeaway

kind (empty) → takeaway

name (empty) → Replace Code Review With Architecture Execution

slug (empty) → replace-code-review-with-architecture-execution

attrs (empty) → {"type" => "recommendation"}

description (empty) → Mateusz Nowak's provocative proposal: replace mandatory code review with an 'architecture review' during planning (wh...

short_description (empty) → Fight for quality at planning time; make code review a formality by executing a pre-agreed architecture.

create Modularity As Business Capability takeaway

kind (empty) → takeaway

name (empty) → Modularity As Business Capability

slug (empty) → modularity-as-business-capability

attrs (empty) → {"type" => "insight"}

description (empty) → Argument from the talk: splitting applications into autonomous modules is not just developer fun — it maps to busines...

short_description (empty) → Well-modularized systems expose business capabilities that can be recombined into new products or paid extensions.

create Developer's Understanding Translates Into Code takeaway

kind (empty) → takeaway

name (empty) → Developer's Understanding Translates Into Code

slug (empty) → developer-s-understanding-translates-into-code

attrs (empty) → {"type" => "insight"}

description (empty) → Closing thought of the talk (a quote Nowak cites). It is not the expert's knowledge that is translated into code but ...

short_description (empty) → It is not the expert's knowledge but the developer's understanding that ends up in the code.

create Delegate Event-Model-To-Test Translation To LLMs takeaway

kind (empty) → takeaway

name (empty) → Delegate Event-Model-To-Test Translation To LLMs

slug (empty) → delegate-event-model-to-test-translation-to-llms

attrs (empty) → {"type" => "recommendation"}

description (empty) → Because Event Modeling specifications already carry given/when/then semantics, translating them into test code is mec...

short_description (empty) → Translating given/when/then specifications to tests is boring and ideal work for juniors or LLMs.

create Internal state in automations question

kind (empty) → question

name (empty) → Internal state in automations

slug (empty) → internal-state-in-automations

attrs (empty) → {"answer_summary" => "Yes — in real processes automations need internal state; even the simplest one at least tracks ...

description (empty) → Audience member notes that on the Event Modeling diagram the read-model view had an arrow into the automation, and as...

short_description (empty) → Does the read-model arrow into an automation mean the automation has internal state?

create Where do calculations live in read models? question

kind (empty) → question

name (empty) → Where do calculations live in read models?

slug (empty) → where-do-calculations-live-in-read-models

attrs (empty) → {"answer_summary" => "Specified by given/when/then examples per view; implementation-wise Nowak repeats the calculati...

description (empty) → Audience asks where calculations (e.g. adding a product to a cart and computing the total) are expressed in Event Mod...

short_description (empty) → In Event Modeling, where do derived calculations like cart totals belong when multiple read models need them?

create Long-running automations and sagas question

kind (empty) → question

name (empty) → Long-running automations and sagas

slug (empty) → long-running-automations-and-sagas

attrs (empty) → {"answer_summary" => "Introduce a saga that consumes multiple events (optionally artificial intermediate ones) and re...

description (empty) → Audience asks who executes commands when an automation is long-running and must wait for multiple events before actin...

short_description (empty) → How do long-running automations that require multiple events get executed?

Edges (43)

update Mateusz Nowak → authored → Might & Magic of Domain-Driven Design

context (empty) → Delivered this talk at wroclove.rb 2025.

update Might & Magic of Domain-Driven Design → presented_at → wroclove.rb 2025

context (empty) → Single-speaker talk at the 2025 edition of the conference.

create Mateusz Nowak → attended → wroclove.rb 2025

context (empty) → Travelled from Poland to speak at wroclove.rb 2025.

relation (empty) → attended

source_node_id (empty) → 352695d4-97a3-49bb-ae17-93bd6701a95f

target_node_id (empty) → 4a9688cf-482e-48ac-a0b5-de88900bdb2b

create Mateusz Nowak → works_at → AxonIQ

attrs (empty) → {"role" => "contractor / developer"}

context (empty) → Contractor at AxonIQ working daily on DDD / event sourcing projects.

relation (empty) → works_at

source_node_id (empty) → 352695d4-97a3-49bb-ae17-93bd6701a95f

target_node_id (empty) → 741e3afd-7d5f-40f7-8695-ea4138052a6f

create Mateusz Nowak → uses → Axon Framework

context (empty) → Uses Axon Framework daily in client work.

relation (empty) → uses

source_node_id (empty) → 352695d4-97a3-49bb-ae17-93bd6701a95f

target_node_id (empty) → f229bdd4-7cc4-4dff-b8d2-cdd6634ac030

create AxonIQ → works_on → Axon Framework

context (empty) → AxonIQ develops and maintains the Axon Framework; its mission is to make event sourcing easy in the Java world.

relation (empty) → works_on

source_node_id (empty) → 741e3afd-7d5f-40f7-8695-ea4138052a6f

target_node_id (empty) → f229bdd4-7cc4-4dff-b8d2-cdd6634ac030

create Mateusz Nowak → authored → DDD Heroes Blog

context (empty) → Author of the DDD Heroes English blog and a companion Polish blog.

relation (empty) → authored

source_node_id (empty) → 352695d4-97a3-49bb-ae17-93bd6701a95f

target_node_id (empty) → 3810584b-e993-41a1-abb3-5bb25b82315d

create Mateusz Nowak → recommends → Event Modeling

context (empty) → Prefers Event Modeling over process-level and design-level EventStorming.

relation (empty) → recommends

source_node_id (empty) → 352695d4-97a3-49bb-ae17-93bd6701a95f

target_node_id (empty) → b9d78e83-eee7-4ef3-9ec5-735739c3897a

create Mateusz Nowak → recommends → Decider Pattern

context (empty) → Recommends the decider pattern (decide/evolve/react) for persistence-agnostic domain logic.

relation (empty) → recommends

source_node_id (empty) → 352695d4-97a3-49bb-ae17-93bd6701a95f

target_node_id (empty) → 257ebe97-c2d6-4102-8515-744da7253cce

create Mateusz Nowak → has_skill → Domain-Driven Design

attrs (empty) → {"level" => "expert"}

context (empty) → Eight years of applying DDD, EventStorming and Event Modeling in commercial projects.

relation (empty) → has_skill

source_node_id (empty) → 352695d4-97a3-49bb-ae17-93bd6701a95f

target_node_id (empty) → 6e2f88bd-e521-41a3-91d4-aeb5f8fd2486

create Mateusz Nowak → has_skill → Event Sourcing

attrs (empty) → {"level" => "expert"}

context (empty) → Daily work on event sourcing via Axon Framework; preferred persistence approach.

relation (empty) → has_skill

source_node_id (empty) → 352695d4-97a3-49bb-ae17-93bd6701a95f

target_node_id (empty) → 687c9da2-de87-4fb2-a758-c7498f394fd5

create Might & Magic of Domain-Driven Design → about → Domain-Driven Design

context (empty) → Central subject of the talk — DDD process and mindset shift.

relation (empty) → about