Khalvai Ozbek

Kaiserslautern, Rheinland-Pfalz, Germany

Software Engineer with +4 years of experience, driven by curiosity about how software systems are designed and evolve.
I focus on understanding the root of business problems to make meaningful change.

TypeScriptNestJSNode.jsPostgreSQLDDDHexagonal Arch.Docker

Solve problem with the least change

Build first and then improve it

Naming is caring

Prefer removing codes over adding

Experience

Where I've worked

Where I've worked, what I built, and how I grew.

Jan 2024 – Jun 2026 · 2 years & 6 months
Software Engineer
Intelika.ai
AI services company building LLM-powered conversational experiences.
- —Utilized microservices to separate and align well with business context and protect ubiquitous langue within the boundary.
- —Reduced message fetching latency by %50, using multi-stage migration: designed presentation service using MongoDB, delegated JWT verification to the service.
- —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.
- —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.
NestJSTypeScriptModular MonolithDDDTeam Leadership
Jan 2023 – Dec 2023 · 1 year
Backend Engineer
Nobati
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.CQRSDDD
Jun 2022 – Dec 2022 · 7 months
Backend Developer
Asrez Group
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

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.