Senior QA Engineer: API, UI & E2E Testing in DDD

Billennium; Warszawa; On-site; PLN 140,000 - 210,000; Full time

Benefits offered by this job

Comprehensive benefits

Career growth

Innovative environment

Engaging community

Team-building events

A pleasant surprise

Job summary

Billennium in Poland is seeking a Senior QA Engineer to join a greenfield project building a core component of a new ecosystem supporting debt servicing and receivables management. You will design test scenarios, validate distributed services and REST APIs, implement automated UI/API/e2E tests using C#/.NET, Cypress or Playwright, and contribute to CI/CD pipelines with GitLab or GitHub Actions.

The role operates in an Agile Kanban environment with close collaboration with Developers and Product

Qualifications

• 4-5+ years of professional experience as a Tester / QA Engineer, including 2+ years in a Senior QA role.
• Strong experience in test automation covering UI, API and/or end-to-end testing.
• Hands-on experience testing distributed systems and service integrations.
• Practical experience with REST API testing.
• Experience with asynchronous communication and event-driven architectures, including queues and messaging.
• Experience creating and maintaining functional, regression and integration tests.
• Practical experience with C# and .NET.
• Knowledge of xUnit, Reqnroll and Shouldly.
• Experience with Cypress and/or Playwright.
• Experience with Testcontainers.
• Experience using Postman and/or Apidog.
• Hands-on experience with GitLab CI/CD and/or GitHub Actions.
• Good knowledge of Git, including branches and merge requests.
• Experience with Jira and Xray for test management, reporting and traceability.
• Practical SQL skills and experience with PostgreSQL.
• Experience working in Agile environments, preferably with Kanban.
• Experience following Domain-Driven Design (DDD) principles.

Responsibilities

• Design, create and maintain test scenarios and test cases covering functional, regression, integration and UAT testing.
• Test distributed systems and integrations between services.
• Test REST APIs and systems based on asynchronous and event-driven communication, including messaging and queues.
• Design, implement and maintain automated UI, API and end-to-end tests.
• Work with C# and .NET, using tools and frameworks such as xUnit, Reqnroll and Shouldly.
• Develop automated tests using Cypress and/or Playwright.
• Use Testcontainers and tools such as Postman or Apidog for API and integration testing.
• Integrate automated tests into CI/CD pipelines, including GitLab CI/CD and GitHub Actions.
• Work with Git, including branching strategies and merge requests.
• Manage testing activities, reporting and traceability using Jira and Xray.
• Use Grafana dashboards and alerts to monitor key quality and system indicators.
• Work with SQL and PostgreSQL to validate data and support testing activities.
• Collaborate closely with Developers and Product Owners to clarify requirements and identify potential quality risks early.
• Contribute to establishing and improving QA standards, testing practices and automation strategies.
• Share knowledge and support less experienced QA team members.
• Leverage AI-powered tools, such as Copilot and LLMs, to improve QA processes, automation and everyday productivity.

Skills

Test automation

REST API testing

Distributed systems testing

C# and .NET

CI/CD pipelines

Git

Jira Xray

SQL PostgreSQL

Agile Kanban

DDD

Tools

xUnit

Reqnroll

Shouldly

Job description

Billennium in Poland is seeking a Senior QA Engineer to join a greenfield project building a core component of a new ecosystem supporting debt servicing and receivables management. You will design test scenarios, validate distributed services and REST APIs, implement automated UI/API/e2E tests using C#/.NET, Cypress or Playwright, and contribute to CI/CD pipelines with GitLab or GitHub Actions.

The role operates in an Agile Kanban environment with close collaboration with Developers and Product