Yalın E.

Real money iGaming platform on Java/Spring Boot microservices: 10–12M game rounds and 18–23M transaction writes a day.

• Wallet transaction p99 latency fell 66% (147.6 to 49.3 ms) and p95 44% over five months; at the peak, with weekly volume up 74%, p99 held at 59.5 ms. My own query consolidation, measured separately: player lookups per transaction down 99%, session queries down 62%.
• Built direct seamless wallet integrations with two major game providers (one carrying 113M rounds in its first full month): idempotent debit, credit and rollback handling, and terminal error codes that ended provider retry loops.
• Led partition pruning on a 10 billion row PostgreSQL transaction table: the worst hot path scan fell from 156 to 4 partitions (10.5 to 1.8 ms). Designed a dedicated idempotency table (0.086 ms average lookup at 20M a day) and a tombstone table for orphan cancels.
• Delivered regulatory automatic withdrawal (120 minute payout rule) in 4 repos before its 1 January 2025 deadline, with negative balance protection and exactly once wallet concurrency tests.
• Found 25–32k game launches a day failing behind HTTP 200, invisible to 5xx monitoring, and drove them to zero. Fixed a provider refund defect that left 2,421 players' rounds open.
• Delivered the first versions of 3 Java/Spring Boot services: live game statistics on Kafka, an operations back office, and a B2B jackpot proxy (the last in about 3 weeks).
• Cut Snyk findings 46% in 6 services; delivered API hardening in 5 repos after a Cloudflare API Shield review.
• Built post deploy verification: 9 Coralogix alerts and automated checks at 15 and 30 minutes; cut the Playwright staging smoke gate from 10m32s to 3m30s; added an 83% JaCoCo gate.
• Authored 3 architecture proposals; the game rounds read model shipped behind a feature flag.

The UCS was developed for the requirements of automated warehouses. It is a vendor-neutral solution that orchestrates automated and human workflows across the warehouse, optimizes order fulfillment end-to-end, and increases productivity. UCS integrates WMS and AMR(Autonomous Mobile Robots) to fulfill needs and creates an environment open for extension. UCS is the first microservice-based application of the company.

• Worked as a full-stack developer in Unified Control System(UCS), mainly focused on the backend. Designed fault-tolerant microservice architecture by creating more than 15 microservices by utilizing RabbitMq message handling.
• Created database per service for every 15+ microservices to ensure scalability of individual microservices.
• Conducted integration and unit testing, including our inner house emulator testing, to ensure the reliability and functionality of the UCS platform with the aim of 80% coverage.
• Performed a load test that can handle 50,000 shipments daily for a warehouse.
• Integrated Geek+ robots into the UCS system to extend and adjust their functionalities into UCS business logic for handling a warehouse with 20 workstations for picking and replenishing shipments.
• Implemented front-end development using Flex Pages and TypeScript, leveraging an in-house front-end framework for the UCS platform.
• Created pipelines using Azure DevOps, managed Maven Artifactory, and implemented Liquibase for database schema management, and Datasync for persisting system data into the database.
• Helped interns and new employees with onboarding and helped them debug and troubleshoot, increasing their sprint speed by 20%.
• Used MirrorD, Konga, and Openlens for Kubernetes development environment.

GeoSolutions is specialized in the processing and dissemination of raster and vector geospatial data with Open Source software according to the standards created by the Open GeoSpatial Consortium (OGC) and the ISO Technical Committee 211, which provide the base building blocks for the INSPIRE regulations.

• Participated in open-source geographic information system (GIS) projects of the company named GeoServer and GeoTools.
• Developed and maintained the open-source projects according to the different clients’ needs by giving consultancy.
• Added modular extensions according to clients' needs. Reproduced their errors and provided faster solutions.
• Worked with CI/CD pipeline and implemented unit and integration tests for all new functionalities.

Nokia Corporation is a Finnish multinational telecommunications, information technology, and consumer electronics corporation, established in 1865.

• Developed a web inventory tracking system for Turkey’s one of the biggest ISPs, which has more than 50 million users.
• Improved system performance and refactored the code.
• Making code more robust and dependency amongst modules is decreased
• Increased the automation capabilities of the system and reduced six days of monthly job to 5 minutes.
• Implemented new modules using Test Driven Development (TDD).
• Wrote unit tests for older classes that have a critical part in the system.

AYESAŞ, as one of the leading solution providers within the Turkish Defence Industry, operates in Aerospace and Defense and has been providing advanced solutions in the business areas of C4ISR, Avionics, Electronic and Electromechanical systems.

• Contributed to the Turkish government's first helicopter projects and first distributed architected UAV mission planning software.
• Developed using Test Driven Development and reach at least 80% coverage in classes.
• Developed microservices using gRPC, which enables bi-directional streaming between user and application while encrypting and gathering data in small packages.