In this episode of Señors @ Scale, Dan sits down with Vlad Kononov, software architect, keynote speaker, and author of Learning Domain-Driven Design and Balancing Coupling in Software Design.

Vlad has spent more than twenty years helping teams untangle legacy systems, rebuild failing architectures, and bring clarity to messy business domains. His work spans greenfield systems, enterprise refactors, and the ambiguous environments where most real software actually lives.

This conversation cuts through the hype around DDD and microservices, focusing on the mechanics of bounded contexts, coupling, business alignment, and architectural evolution. We talk about why ubiquitous language reduces project failure, how bounded contexts emerge from social structures rather than diagrams, why most teams misuse aggregates, and how to spot “pain signatures” inside a system and trace them back to unclear domain boundaries. Vlad explains how subdomains evolve over time, how good designs quietly become counterproductive, and how accidental complexity appears at every layer of a system.

We also dig into the real model behind coupling—strength, distance, and volatility—and how teams can use it to design systems that stay adaptable under pressure. Vlad breaks down why many microservice rewrites fail, when DDD actually makes sense, and why refactoring should start with understanding the business rather than carving out services at random.

The episode ends with a discussion about AI and architecture, and how LLMs make domain-driven design more important rather than less. Vlad explains why clear domain vocabulary and modular boundaries help both engineers and AI reason about a system without being overwhelmed by complexity.

If you’re building complex systems, leading platform or architecture teams, or struggling with a legacy codebase that keeps pushing back, this episode offers a practical, experience-driven guide to designing systems that scale with the business.

Chapters

00:00 Intro and Vlad’s Background
01:42 Why DDD Was Written and Who It Was For
04:02 When Aggregates Finally Made Sense
05:42 Ubiquitous Language as the Core of DDD
07:31 Why Software Projects Fail
08:52 The Biggest Misconception About DDD
10:13 Common Anti-Patterns in Domain Design
12:12 Greenfield vs Brownfield DDD
14:03 How to Begin Refactoring a Monolith
15:25 Mapping Subdomains: Core, Supporting, Generic
19:25 When Companies Do DDD Without Knowing
20:39 When DDD Fails and Lessons Learned
22:41 Why Defining Boundaries Is Hard
25:56 Accidental Complexity in Large Systems
27:32 Microservices, Myths, and Pain
30:29 What Coupling Really Means
33:17 Strength, Distance, and Volatility
39:07 How Vlad Documents Architecture
41:37 Event Storming as the Source of Truth
44:01 How AI Changes System Design
48:28 How to Enforce Ubiquitous Language
51:00 Book Recommendations
53:33 Closing Thoughts

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