
Deniz Hamamcioglu
Verified Expert in Engineering
Quality Assurance Developer
Ankara, Turkey
Toptal member since December 12, 2018
Deniz is a visionary QA architect and automation lead with 12+ years of experience designing, building, and scaling enterprise-level test automation frameworks. He's recognized for leading teams, spearheading technical initiatives, and developing validation systems. Deniz is adept at tackling highly complex projects and has a track record of mentoring global teams, driving engineering best practices, and ensuring uncompromising quality standards for industry leaders such as Google and Amazon.
Portfolio
Experience
- JavaScript - 12 years
- Python - 12 years
- Java - 12 years
- API Testing - 10 years
- Selenium - 10 years
- QA Automation - 10 years
- TypeScript - 8 years
- Playwright - 6 years
Preferred Environment
Java, JavaScript, Python, TypeScript, Playwright, Selenide, Selenium, Appium, Cypress, WebdriverIO
The most amazing...
...thing I've done is leading quality across every tier, from low-level firmware, web, and mobile to load testing and AI evaluation for industry-leading platforms.
Work Experience
QA Automation Engineer
55labs GmbH
- Architected a robust test and monitoring framework specifically for LLM validation using Python and deepeval.
- Engineered complex evaluation methodologies incorporating custom logprob and semantic entropy calculations to dynamically measure AI model confidence and proactively flag hallucinations.
- Designed and implemented automated UI tests utilizing Python and Playwright, seamlessly integrated into GitHub CI pipelines.
Senior QA Engineer
Personio - Main
- Architected a scalable test automation framework leveraging TypeScript and Playwright for critical web applications.
- Implemented robust automated functional and visual comparison tests to safeguard the UI integrity of the main platform.
- Constructed and optimized CI/CD pipelines in GitLab and GitHub for continuous automated test execution and deployment validation.
- Authored comprehensive technical documentation and established test automation best practices across engineering teams.
- Implemented automated accessibility tests for every domain and page that the platform has.
Lead Software Engineer in Test
Google (via Applause)
- Architected and deployed an end-to-end test automation framework from scratch for high-traffic web and mobile testing domains.
- Led and mentored a specialized team of six engineers to automate the Google Search application for the shopping domain.
- Engineered comprehensive unit, component, and WebDriver tests for Google Travel, aligning manual test logic with automated coverage.
Senior Mobile Test Automation Engineer
Bragi
- Engineered a custom test automation framework (Python, Pytest, and Appium) from the ground up for highly complex embedded audio devices and firmware operations.
- Developed custom frameworks for strategic Amazon projects, ensuring high reliability across iOS and Android ecosystems.
- Innovated an AI-driven failure analysis system capable of parsing screenshots, stack traces, and test steps to autonomously classify failures and determine root causes using scientific confidence metrics.
- Designed fully automated audio testing and voice command validation protocols to detect and verify specific auditory outputs from hardware devices.
- Architected and managed a globally distributed custom device farm combining on-premise infrastructure and worldwide servers, fully integrated with end-to-end CI/CD pipelines in GitLab.
- Orchestrated complex multi-device integrations spanning the Google ecosystem (Gmail, Firebase, and Chirp3) and Microsoft Teams.
Test Automation QA Engineer
Leading Quality Assurance Ltd
- Built a unified test automation framework targeting mobile applications, web admin panels, and back-end API endpoints.
- Leveraged BrowserStack to massively scale test execution across a wide matrix of devices and operating systems.
- Integrated the automation suite with CI/CD pipelines (GitHub Actions) and customized Slack reporting for real-time visibility.
QA Automation Engineer
BNP Media, Inc.
- Developed a test automation framework using TypeScript and Cypress.
- Implemented GitHub Actions CI pipelines to validate the business-critical user journeys.
- Performed automated data validation testing, comparing data spanning across multiple database migrations.
Lead Automation Engineer
Mesh Connect
- Designed the overarching test automation architecture for high-stakes API endpoints interfacing with major financial institutions and brokerages.
- Developed a modular Python framework engineered to handle complex authentication flows, captcha bypassing, and comprehensive API and UI coverage.
- Designed the technical framework for rigorous scale validation and led load testing initiatives using JMeter under high-stress conditions.
- Defined and enforced engineering standards, including branching strategies, code reviews, and coding conventions.
QA Automation Expert
Causemetric LLC
- Developed a Playwright-based test automation framework.
- Created QA approach, automation, coding, and review guidelines.
- Integrated the automated test solution with the CI pipelines to enable continuous testing.
Senior Automation Engineer
United Nations
- Enhanced and maintained a comprehensive suite of Playwright-based automated tests for mission-critical applications.
- Engineered automated data validation pipelines utilizing CosmosDB.
- Developed extensive load testing protocols with JMeter and authored organizational best practice guidelines.
Automation Lead
Star
- Architected the complete test automation strategy for a regulated medical device and its corresponding native mobile application (iOS and Android).
- Unified web, API, and mobile testing into a single, cohesive Python-based framework.
- Engineered a custom device farm and configured Jenkins CI pipelines, increasing automated test coverage from zero to over 85%.
QA Architect
Deckers - Deckers US
- Led global quality assurance for five major brands across four regions, serving tens of millions of daily users.
- Managed, mentored, and scaled a high-performing team of seven senior QA and automation engineers.
- Resolved critical framework instabilities and flakiness through strategic architectural overhauls of the legacy automation suite.
- Directed enterprise load testing efforts and orchestrated complex release testing processes.
QA Architect
Deckers Brands
- Managed a team of seven highly skilled QA engineers in charge of automation framework development, maintenance, release testing, R&D activities, and load testing.
- Architectured the entire test approach for a new microservices product that replaced all the existing eCommerce sites of the company and was used by millions of people worldwide.
- Spearheaded the release of exploratory and regression testing for five eCommerce sites spanning three continents and used by millions of people.
- Enhanced the existing test automation framework architecture to make the automated tests more stable.
- Constructed CI pipelines for automated tests using GitLab.
- Led the effort to prove concepts of new technologies adapted to our existing solution set.
- Conducted technical interviews to hire new QA engineers.
- Led the effort for architecting load tests for the holiday readiness season.
- Helped design a test automation framework using Playwright and JavaScript to conduct web, API, component, and UI performance tests for a microservices project.
Mobile QA Engineer
Digital-arm (via Toptal)
- Led the overall testing effort for a mobile application that targets thousands of simultaneous users.
- Performed load tests using JMeter and Gatling tools.
- Designed test cases and performed regular smoke and regression tests.
Senior QA and Test Automation Engineer
Haiilo
- Spearheaded the test automation effort across the company.
- Designed and developed an E2E test automation framework capable of automating UI, mobile, and API tests from scratch using Java, Selenide, and TestNG.
- Provided training and guidelines about test automation, API testing, RESTful APIs, Java coding best practices, testing approaches, and strategies to the other team members.
- Led the effort to search for new technologies for test automation.
- Integrated the automated tests to the CI/CD pipelines using Docker and GitLab.
Senior Test Automation Engineer
Yara
- Developed a test automation framework using Cypress, JavaScript, and Cucumber used by multiple teams and various products.
- Provided regular workshops about test automation best practices and programming with JavaScript and Cucumber.
- Implemented guidelines about coding conventions, branching strategies, pull request reviews, and test automation best practices.
QA Engineer
Foreign Credentials Service of America (via Toptal)
- Developed a test automation framework from scratch, using Protractor, JavaScript, and Docker.
- Fixed both UI and back-end bugs that were found by me during exploratory testing.
- Wrote unit tests for both the front end and back end to increase code coverage.
- Designed test cases, extensive documentation, and test strategy.
- Executed exploratory tests as well as regular test sessions.
- Performed regression and smoke tests with each release cycle.
- Streamlined CI/CD deployment pipelines utilizing Jenkins and Docker.
- Transitioned legacy E2E test automation from Protractor to a modernized Playwright framework.
Senior QA Automation Engineer
Friend Finder Networks (via Toptal)
- Provided training to the other team members about test automation best practices.
- Reviewed automation code that was written by other junior team members and provided mentorship.
- Gave training about RESTful APIs, API test automation, and back-end testing.
- Designed test cases and test plans for multiple products.
- Developed test automation scripts that are used both in front-end and back-end testing.
- Created a test automation framework that was used across multiple teams and products.
Expert QA Engineer
Amadeus IT Group (Global Travel and Tourism Industry)
- Developed a custom test automation framework for the company product using TypeScript and Protractor.
- Wrote test automation scripts that are used across multiple teams.
- Conducted API testing using Postman and a custom in-house scripting tool.
- Designed test cases and test scenarios for multiple products.
- Executed regular regression and exploratory tests.
- Participated in R&D activities and regularly explored new technologies to be used inside the company tech stack.
- Developed and executed load tests and provided detailed metrics to the development and business teams.
Test Analyst
Accenture Industrial Software Solutions (Global Management Consulting)
- Developed a test automation framework for web applications using Java and Selenium.
- Created automated UI tests for desktop web applications.
- Wrote automated UI tests for mobile applications using C#, Xamarin.UITest, and Java-Appium.
- Developed document-manipulating software using Python.
- Wrote API test automation scripts using Postman and SoapUI.
- Worked on front-end bug fixes using TypeScript-Angular.
- Designed and executed test scenarios for products that are used by thousands of people.
- Created test strategy and test plans document for multiple projects.
- Conducted regular exploratory and regression test sessions and provided root cause analysis to the development teams.
Test Engineer
Havelsan, Inc. (Defense Industry)
- Supported the development of a custom test automation software by implementing record-and-play functionality to do real-time memory injections to full mission military simulators.
- Developed traceability, document creation, and manipulation software using Python.
- Designed, reviewed, and executed test cases for full mission military simulators.
Experience
Java and Selenide Test Automation Framework
Framework features:
• Modular design with Page Object Modal architecture
• Extremely stable, maintainable, and readable
• Easy to work with thanks to its design that implements near-English test step methods
• Ability to measure load times
• Ability to intercept and manipulate HTTP requests and responses
• Ability to send API calls to set up software configuration and test data
• Detailed Allure Test Reports with historical data
• Full integration with GitLab
• Docker and Docker compose set up
Java Test Automation Framework
Framework Features:
· It was designed according to POM (Page Object Model).
· Implements page and element factory structures.
· Possesses extensive reporting capabilities.
· Validates database entries and file contents.
· Has the ability to use external DOCX, DOC, XLS, XLSX, CSV, and JSON files for inputting test data.
Python and C++ Based Custom Test Automation Software
This Python-based automation software was used in conjunction with a separate C++ based software in order to perform memory injections.
Native Mobile App and Firmware Validation Test Framework
The overarching architecture features:
• Hardware and Audio Validation: Designed specialized protocols for embedded device firmware that automatically issue voice commands and utilize Chirp3 for precise auditory output detection and validation.
• Infrastructure and CI/CD: Architected and managed a globally distributed, custom device farm combining on-premise hardware and worldwide servers, fully integrated into GitLab CI/CD pipelines for continuous execution.
• Ecosystem Integrations and Operations: Orchestrated complex multi-device workflows utilizing Firebase for dynamic download operations, integrated Google APIs (Gmail), and leveraged Microsoft Teams for real-time automated result broadcasting.
• Autonomous AI Diagnostics: Innovated an AI-driven failure analysis engine powered by advanced LLMs (including Gemini and Claude) that parses screenshots, test steps, and stack traces to autonomously classify failures and determine root causes using scientific confidence metrics.
LLM Evaluation Framework
Key framework capabilities include:
• AI Model Evaluation: Architected a robust LLM validation and monitoring framework from the ground up, utilizing Python and deepeval.
• Hallucination Detection and Metrics: Engineered complex evaluation methodologies that leverage custom logprob and semantic entropy calculations to dynamically measure AI model confidence and proactively flag hallucinations.
• UI Automation and CI Integration: Designed and implemented automated UI tests using Python and Playwright, seamlessly integrating end-to-end front-end validation directly into GitHub CI pipelines.
UI, Visual, and Accessibility Automation Framework
Key framework capabilities include:
• Functional, Visual, and Accessibility Testing: Implemented comprehensive automated functional and visual comparison tests to proactively safeguard the main platform's UI integrity, alongside automated accessibility checks to ensure an inclusive and compliant user experience.
• CI/CD Pipeline Optimization: Constructed and optimized end-to-end CI/CD pipelines across both GitLab and GitHub, enabling continuous automated test execution and robust deployment validation.
• Standardization and Documentation: Championed quality engineering by authoring detailed technical documentation and establishing standardized test automation best practices across multiple engineering teams.
Unified Mobile, Web, and API Automation Framework Summary
Key framework capabilities include:
• Full-stack Test Coverage: Engineered a cohesive testing suite targeting mobile applications, web interfaces, and back-end APIs to ensure end-to-end system reliability.
• Massive Execution Scale: Leveraged BrowserStack to massively scale automated test execution, ensuring robust coverage across a wide matrix of devices and operating systems.
• CI/CD and Real-Time Reporting: Integrated the complete automation suite into GitHub Actions CI/CD pipelines, augmented with customized Slack integrations to provide real-time visibility into test execution results.
Education
Bachelor's Degree in Computer Technology and Information Systems
Bilkent University - Ankara, Turkey
Certifications
ISTQB Foundation Level
International Software Testing Qualifications Board
Skills
Libraries/APIs
Node.js, Selenium WebDriver, Chai, WebDriver, AssertJ, Playwright, Google APIs, Google API
Tools
IntelliJ IDEA, Confluence, Bitbucket, TestRail, GitLab, Mocha, SuperTest, Jira, HP Application Lifecycle Management (ALM), Postman, Apache JMeter, Cucumber, REST Assured, Git, PyCharm, Bamboo, Jenkins, WebdriverIO, BrowserStack, SoapUI, CircleCI, Visual Studio, Gatling, Pytest, GitHub, GitLab CI/CD, GitLab Runner
Languages
JavaScript, Python, Java, TypeScript, ECMAScript (ES6), TypeScript 2, C++, PHP, C#
Frameworks
TestProject, Selenium, TestNG, Appium, Protractor, TestCafe, Cypress, Allure Testing Framework, Selenide, Angular, Laravel, React Native
Paradigms
Manual Testing, Automation, Automated Testing, REST, Test Automation, Load Testing, Page Object Model (POM), Scrum, Agile, Kanban, Behavior-driven Development (BDD), Microservices, Software Testing, E2E Testing, Unit Testing
Platforms
Docker, Linux, Visual Studio Code (VS Code), Salesforce, Elastic Path, Xamarin, Google Cloud Platform (GCP), Firebase, iOS, Android, Azure, Amazon Web Services (AWS), Vercel
Storage
MySQL, Azure Cosmos DB
Other
Quality Assurance (QA), Mobile App Testing, Manual QA, QA Automation, QA Leadership, QA Testing, Test Management, Test Design, ISTQB, Regression Testing, Exploratory Testing, API Testing, APIs, ExtentReports, Apache Commons, Axios, Software Architecture, Release Management, BlazeMeter, REST API Automation, Artificial Intelligence (AI), Back-end Development, Software Development, Data-level Security, Software Engineering, Mobile App Development, CI/CD Pipelines, Large Language Models (LLMs), FastAPI, LLM Agents, AI Agents, Agentic AI, AI Evaluation, LLM Evaluation, deepeval, Agno, Temporal, MLflow, Firmware Testing, Audio, PWA, Integration Testing, Visual Regression Testing, CAPTCHA, Android Testing, GitHub Actions, Axe
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