🧪 Freelance Senior QA Engineer (Mobile) bei Unzer in Berlin – POS Hardware & Software Quality Expert

About Unzer

Unzer is a prominent European fintech organization focused on streamlining international payment processes for e-commerce and retail merchants. Originating from 13 merged enterprises, our unified platform powers complete payment journeys. Our global workforce of over 700 professionals across 55 nationalities works collaboratively to deliver exceptional unified commerce solutions.

Role Overview

As part of the Unified POS team, you will drive quality assurance for Android and iOS mobile POS software. You will ensure smooth operation and elevated service quality while testing applications that interface directly with physical hardware like receipt printers, barcode scanners, and payment terminals.

Key Responsibilities

• Architect, build, and maintain robust test automation pipelines using TypeScript and Sauce Labs
• Formulate and maintain structured test plans within Xray and Jira for existing and upcoming features
• Conduct, maintain, and refine test scenarios in Xray to improve overall workflow integration
• Perform hands-on hardware integration tests with payment terminals, scanners, and printers
• Validate inter-device communication protocols across multiple internal applications
• Design cross-functional test scenarios spanning API communication and database operations
• Incorporate modern AI tools into daily quality assurance workflows to drive innovation
• Partner with software developers and product owners to achieve extensive multiplatform E2E test coverage
• Participate actively in code reviews to enforce software standards and code performance
• Execute multi-environment testing to confirm system stability and software compatibility

Technical Ecosystem

The team currently leverages TypeScript, Webdriver.io, Java-based tooling, PostgreSQL, SQLite, Xray, and Jira.

Required Qualifications

• Availability to work on-site at our Berlin office at least twice a week for hardware testing
• 4+ years of professional background in mobile application testing across iOS and Android platforms
• Proven experience in test automation utilizing TypeScript alongside tools like Sauce Labs or Appium
• Solid expertise in test case design principles and industry standards
• Strong command of relational databases, specifically PostgreSQL and SQLite
• Proficiency with API testing tools such as Postman
• Practical knowledge testing physical hardware integrations and device communication
• Structured approach with a proactive mindset toward early test planning

Desirable Experience

• Familiarity with Playwright and Selenoid
• Background in fintech, payment processing, retail, or gastronomy POS platforms

Application Process

Submit your application with an English resume. The multi-stage review process includes an introductory call with talent acquisition, a technical hiring manager interview, a practical take-home assignment, and a peer discussion.