Senior QA Engineer (.NET, Integration & Batch Testing)

We’re looking for a QA Engineer to join a global technology and IT services organization supporting large-scale system modernization programs for enterprise clients.

The team works on transforming complex, business-critical systems from legacy platforms into modern .NET and cloud-based solutions, with a strong focus on quality, stability, and data integrity.

The role is part of a long-term modernization initiative involving backend systems, batch processing, integrations, and message-driven workflows. You’ll collaborate closely with developers, data engineers, and platform specialists to ensure that modernized applications behave consistently with legacy systems during parallel runs and cutover phases.

Key responsibilities

• Design and execute manual and automated tests for .NET C# applications resulting from mainframe modernization

• Perform batch job and integration testing, including validation of long-running and scheduled processes

• Validate functional equivalence between legacy mainframe processes and modernized .NET/Azure solutions

• Test message-driven workflows and integrations using messaging systems (e.g. Azure Service Bus, IBM MQ)

• Execute regression, integration, and data consistency tests across interconnected systems

• Create and maintain automated tests using .NET test frameworks and integrate them into Azure DevOps CI/CD pipelines

• Analyze batch outputs, logs, audit trails, and data flows to ensure accuracy and completeness

• Collaborate with developers, data engineers, architects, and mainframe SMEs during parallel runs and cutover phases

Ideal candidate profile

• Experience in QA / test automation for .NET C# backend systems

• Hands-on experience with batch processing and integration testing

• Knowledge of API testing (e.g. Postman / Newman)

• Experience working with Azure DevOps (pipelines, test plans, CI/CD)

• Good understanding of SQL and data validation in data-intensive systems

• Experience testing asynchronous or message-based systems

• Comfortable working in Agile and DevOps environments

Nice to have

• Exposure to mainframe systems or modernization projects

• Experience with IBM MQ or Azure Service Bus

• Knowledge of batch orchestration and scheduling tools (e.g. Control-M, PowerShell)

• Background in industries with complex legacy systems (e.g. manufacturing, financial services, insurance)

Conditions

• Work model: remote

• Salary: 150-210 pln/h

• Employment type: B2B

• Benefits: medical care, life insurance, trainings, Multisport card

Recruitment steps

• Phone call with Recruiter (20 - 30 min.)

• Technical interview with Client (may required 2 rounds)

• Feedback and decision