Picture of Onur Haktan

Onur Haktan

Software Engineer

Software engineer with 2+ years of experience modernizing business-critical banking systems — migrating legacy platforms to Java/Spring Boot microservices for capital markets and individual pension systems. Currently building transaction-critical workflows at Garanti BBVA Technology using event-driven architecture (Kafka, RabbitMQ), gRPC, and React in regulated financial environments.

Technologies

JavaSpring BootReactSQLgRPCApache KafkaRabbitMQRedisOracleDocker

Architecture & Methodologies

MicroservicesREST APIsEvent-Driven ArchitectureOOPSOLIDDesign PatternsUnit TestingAgile/Scrum

Experience

Software Engineer

Garanti BBVA Technology · via Linktera

Oct 2025 – Present

Remote

  • Contribute to the modernization of Individual Pension Systems, migrating legacy CoolGen-based applications to microservices using Java, Spring Boot, Kafka, gRPC, React, and Oracle.
  • Develop modern React-based interfaces to replace legacy screens, including workflows for individual pension exit operations.
  • Applied AI-assisted development with a focus on model selection, context management, and token efficiency, using capable models for complex tasks and lightweight models for simpler tasks.
  • Implement backend processes for pension exit workflows, including automated email, SMS, and document delivery following transaction completion.
  • Participate in high-level and low-level system design, including service design, data modeling, and database schema design using PowerDesigner.

Software Engineer

Yapı Kredi Technology · via Metasis Technology

Jun 2024 – Oct 2025

Remote

  • Engineered the migration of capital markets and investment systems from legacy applications to microservices using Java, Spring Boot, Kafka, RabbitMQ, Redis, React, and Oracle.
  • Delivered core workflows for the microservices transformation of the IPO platform, covering IPO management, allocation, and payment processing, including batch jobs, file generation and transfers, notifications, and integrations with core banking and provisioning systems.
  • Built a corporate actions notification workflow for international equities, processing brokerage documents, matching events with customer portfolios, and delivering personalized email and SMS notifications for events such as dividend payments.
  • Integrated document-based capital markets operations with the bank's workflow management platform, enabling branch-initiated and standalone transaction flows through microservices-based services.
  • Maintained project-level code coverage requirements of at least 80% by developing unit tests for backend services and business workflows.

Software Developer Intern

Eczacıbaşı Bilişim

Mar 2024 – May 2024

Remote

Java Developer Intern

E-Commint

Aug 2023 – Oct 2023

Remote

Projects

Individual Pension System – Retirement Exit Module Modernization

Contributed end-to-end to modernizing a pension retirement exit module at Garanti BBVA Technology — core workflows, document generation, notifications, and React interfaces, applying Strategy and Factory design patterns. Built with Java, Spring Boot, and Oracle.

JavaSpring BootReactOracle

IPO Platform Modernization

Contributed end-to-end to modernizing a legacy stock IPO platform at Yapı Kredi Technology into Java/Spring Boot microservices — covering allocation, provisioning, payments, approvals, and a React frontend, with integrations across core banking systems.

JavaSpring BootReactOracle

Morning Wire

Daily personalized SMS briefing pipeline covering markets, portfolio, news, sports, and language study — summarized via the Claude API and delivered serverlessly through GitHub Actions.

PythonGitHub ActionsClaude API

Kutla!

AI-assisted mobile app that generates personalized celebration visuals for holidays and special occasions by orchestrating requests to image generation models.

AI AgentsImage Generation

Eye Disease Classification from Fundus Images

Deep learning system (VGG16, ResNet50) for classifying eye diseases from fundus images with Grad-CAM explainability — 1st place, graduation thesis.

Deep LearningVGG16ResNet50Grad-CAM