Crash Course: Domain Driven Design
Mentor — Vitalii Hryhoryshyn, Team Lead at Balto Health, 19 years in IT
How to measure, show, and defend boundaries in a system that's already in production
Most DDD material teaches you to draw boundaries on a blank sheet of paper. This course is for systems that are already running in production: with an accumulated history of decisions, legacy code, and dependencies nobody planned for. A senior developer's intuition is usually right, but you can't put it on the table — check it, hand it to the team, or defend it to management. Here, boundaries aren't found on sticky notes but in the history of your code and data — so that ‘I feel the boundary is here’ turns into an argument people will agree with.
Mentor: Vitalii Hryhoryshyn, Tech Lead, 19 years in IT.
Using real cases, you'll learn to find context boundaries from evidence already present in your system, calculate the cost of each boundary, and lock it in place so it doesn't erode over time.
By the end of the course, you will:
- be able to find boundary candidates in your own system from code and data facts, not gut feeling
- learn to calculate the cost of a boundary: in change velocity, release coupling, and cross-team coordination cost
- understand why systems already split into services keep behaving like one
- be able to justify an architectural decision so both the team and the business accept it
- lock the boundary into the build, so you don't have to defend it by hand
- Senior developers responsible for architectural decisions
- Architects and tech leads
- Anyone who has tried to draw boundaries in a system — and couldn't explain to the team why exactly there
Three webinars: find, draw, hold the boundaries
session-1 Finding boundaries Oct 13 · 1/3 ›
- – Subdomain, Bounded Context, service, database, team: what doesn't line up with what, and what it costs you
- – Sources of evidence: co-changes in code, feature scatter, transaction boundaries, actual code ownership
- – Live walkthrough: from git log to a coupling heatmap
- – From numbers to a decision: why metrics don't show you the domain — they only rule out bad boundaries
- – Cases: a boundary drawn along the database schema; a boundary that matched a team boundary
session-2 Drawing boundaries Oct 15 · 2/3 ›
- – The Context Map as a technical contract, not a diagram: relationship types and the cost of each
- – The Anti-corruption Layer: where to put it, when it's unnecessary, and how to avoid it becoming a second model
- – A shared database as the cheapest way to destroy a boundary you just drew
- – From context boundary to slicing Aggregates
- – Architecture Decision Records (ADR): capturing a decision along with its cost
- – Cases: integration through a shared model and the bill for it; a decision that failed to get buy-in
session-3 Holding the boundaries Oct 17 · 3/3 ›
- – Aggregate as a transaction boundary: what must be consistent within a single transaction
- – When a split system still behaves like one: diagnosing it in numbers, and why it's an integration mistake, not a decomposition one
- – Enforcing the boundary in CI: a rule that fails the build on a forbidden import between contexts — we walk through a working one and break it live
- – What holds the boundary under load: atomic event writes alongside state, delivery-failure behavior, consumer-side idempotency
- – Where to go next: evolving boundaries on a live system
An end-to-end project on your own repository: a coupling matrix → an ADR for one boundary → a rule that fails on a forbidden import across that boundary. The rule runs locally; wiring it into CI is optional.
The mentor isn't grading your domain's business logic, but the mechanics of the method: does the boundary follow from the metrics you cite, is its cost named, and were alternatives considered.
Vitalii Hryhoryshyn
- – 19 years in IT, 13 of them in high-load systems and e-commerce
- – Leads two teams — development and analytics. Hence the approach: architectural boundaries can be not just felt, but calculated
- – Mentor at Fwdays Academy, author of architecture courses
- – Founder of think.wider.ukraine (technology and business, explained simply)
- – Builds healthy boundaries. Mostly in other people’s systems.
Event price
Access to online broadcasts (~10 hours)
Presentation and materials
Access to the course recording on the learning platform
Access to the chat in the TG, where the speaker will answer questions
Participant certificate subject to completing homework
Free month in Fwdays Club
10% discount on participation in Fwdays conferences
Available payment in installments from Monobank and purchase in installments from PrivatbankIf after the first lesson you realize that your expectations do not match, we will refund the money in full.