My professional experiences below showcase my ability to bring ideas to life, whether it’s creating MVPs from scratch or launching brand-new projects within established companies. From initial concept to building and leading teams around these initiatives, I have consistently delivered results that drive impact. While these examples highlight my capabilities in professional settings, my personal projects offer an even deeper glimpse into my creativity and passions.
Garanti Technology • Software Engineer • 1999 – 2002
Garanti Bank, Turkey’s third-largest bank in 1999, provided me with my first experience working in a large corporate environment. Garanti Technology provided technology services to Garanti Bank, as well as 2 other banks within the group. Adjusting to a workplace with hundreds of developers and strict corporate protocols (like wearing a suit every day) was a formative experience. I was part of the credit cards team, which handled both credit card issuance and merchant services, developing innovative solutions on IBM's S/390 mainframe.
During my tenure at Garanti Bank, I gained invaluable experience with large-scale systems, advanced transaction processing, and cutting-edge innovations in banking technology. I also expanded my technical skillset, working with mainframe technologies (CICS, PL/1, and DB2), POS software, and AIX-hosted web applications. In late 2002, I left Garanti Bank to pursue an MBA in San Diego, embarking on the next phase of my professional journey.
Credit Card Server Optimization and DB2 Migration: Refactored and migrated the credit card server backend (ISO 8583 electronic payment server) from VSAM files to DB2. This significantly reduced transaction timeouts caused by concurrency limits and improved peak day performance from 7-8 seconds to under 1 second, enabling a record transaction volume of 700K+ in a single day. Re-engineered core components on CICS using PL/1, resolving critical bottlenecks, including "lava flow" code.
EMV Migration and Chip-Based Loyalty Program: Contributed to the innovative EMV migration project, transitioning the bank's credit card system to chip-based technology, years ahead of the U.S. market. Played a significant role in developing and testing Turkey's first major chip-based loyalty program, Bonus Card, which stored rewards directly on the chip and allowed redemption via Ingenico POS devices.
Temporary Credit Cards: Integrated a bank mainframe CICS, with a web application on an Apache server hosted on AIX. The web interface was developed in C++ to provide temporary credit cards, which led to an increase in monthly transactions by over $50,000.
Innovative Email-Based Statements: Developed a C program with BSD sockets on OS/390 Unix emulation mode to send email-based credit card statements, reducing paper costs and introducing a forward-thinking eco-friendly solution for the time.
Recurring Billing Solution Optimization: Fixed bugs and refactored the in-house recurring billing system used by member merchants, achieving a record transaction volume of 100K+ monthly transactions.
Technologies: PL1, C, VB6, JCL, TSO, CICS, Apache, DB2, OS/390, AIX.
