I prioritize doing things right over doing things fast and love building systems for long-term usage,
making them understandable for future engineers.
// how I think about hierarchies
Experience
Where I've worked
Where I've worked, what I built, and how I grew.
Nov 2025 – Jun 2026 · 8 months
Senior Software Engineer
AI services company building LLM-powered conversational experiences for enterprise customers.
- —In close collaboration with marketing team, engaged users to become customers in Finance service, by designing a system that offers trial subscriptions.
- —Implemented a notification service, using event-driven architecture, to notify customers to renew the past-due subscriptions.
- —Collaborated with DevOps engineers to define deployment architecture and improve production delivery workflows.
- —Reduced message fetching latency by %50, using multi-stage migration, designing presentation service using MongoDB, delegation of JWT verification to the service.
NestJSTypeScriptModular MonolithDDDTeam LeadershipJan 2024 – Nov 2025 · 2 years
Software Engineer
AI services company building LLM-powered conversational experiences for enterprise customers.
- —Implemented Stripe subscription workflows and integrated them with internal billing logic for automated monthly star refresh.
- —Supported a team of 4 engineers in adopting Domain-Driven Design (DDD) and Hexagonal Architecture through structured knowledge-sharing sessions.
- —Built an internal NestJS seedwork implementing DDD tactical patterns (Entities, Value Objects, Aggregates, Repositories), enabling consistent domain modeling across microservices.
- —Decoupled communication protocols, HTTP and gRPC, from business logic, making the logic more understandable.
- —Implemented inbox/outbox pattern, ensuring eventual consistency and idempotency of events.
- —Discovered business bonded contexts and integrated domain model concepts into existing N-Layered Architecture.
NestJSTypeScriptDDDgRPCMicroservicesJan 2023 – Dec 2023 · 1 year
Backend Engineer
Appointment management platform offering tailored scheduling solutions for businesses, serving over 200,000 users.
- —Solved payment issues and subscription issuance problems for users, creating a convenient purchase flow.
- — Migrated JavaScript codebase into TypeScript, using DDD, improving separation of concerns.
- —Planned parallel development of legacy repositories alongside integration with new services.
- —Contributed to the success of a company serving over +200K users by prioritizing solving existing challenges.
- —Solved concurrency issue of reserving a slot of time for a user, using two level locks in the business process.
NestJSTypeScriptHexagonal Arch.CQRSDDDJun 2022 – Dec 2022 · 7 months
Backend Developer
Web technology consultancy delivering creative software infrastructure solutions to clients.
- —Developed APIs using REST and GraphQL to support diverse client applications.
- —Implemented an N-layered architecture in NestJS, ensuring scalability, testability, and clear separation of concerns.
NestJSTypeScriptRESTGraphQL
Writing
Latest posts
Notes on software architecture, TypeScript patterns, and lessons from the field.
Data Inconsistency in Distributed Systems: Problem Patterns & Practical Solutions
Explore why data inconsistency happens in modern distributed systems, and learn proven patterns to tackle cross-service consistency, from basic transactions to inbox/outbox and saga patterns. Includes practical TypeScript examples.
#distributed-systems#data-consistency#transactions#patterns#typescriptWrong Abstractions: The Type Safety Trap
Why most TypeScript interfaces in modern web apps aren't real abstractions—and how overusing them for 'type safety' leads to code coupling and anti-patterns. Learn better approaches, with practical NestJS/TypeScript examples.
#abstraction#typescript#architecture#nestjs#anti-patternsDDD in Practice: The Value Object you're not writing
Most teams adopt DDD vocabulary but skip Value Objects because they feel like boilerplate. Here's why that's a mistake and how to introduce them without rewriting your codebase.
#ddd#typescript#architectureClean Architecture with NestJS: A practical guide
NestJS modules map naturally to Clean Architecture layers — here's how to structure your project so that your domain stays framework-free and your tests stay fast.
#nestjs#typescript#clean-architecture
Talks
On stage
Conference talks and university workshops on architecture, patterns, and developer craft.
28 Dec 2024 · FullstacksJS YouTube Channel
Software Architecture and Hidden Costs
Trade-offs and how to avoid long-term architectural costs.
watch seminar →
20 May 2024 · Vali-e-Asr University
Software Architecture
The importance and history of software architecture — from monoliths to modern distributed systems.
22 Apr 2024 · Vali-e-Asr University
Design Patterns
The importance of patterns with live demonstrations of real-world applications.
9 Feb 2023 · Vali-e-Asr University
Clean Code Principles
Clean code principles explained with annotated code samples and live refactoring.
Contact
Get in touch
You also care about patterns and architecture?
I'm open to discuss, feel free to contact me.
- Emailkhalvayozbek@gmail.com
- GitHubgithub.com/khalvai
- LinkedInlinkedin.com/in/khalvai-ozbek
- Telegramt.me/khalvai