Senior Full-stack Test Engineer

Responsibilities
We are looking for a Senior Full-stack Test Engineer to take end-to-end ownership of quality for a System Integration Testing (SIT) project, combining strong manual testing depth with hands-on test automation.
This is an SIT role, not a UAT role. You will validate how multiple systems behave together - verifying business flows end to end, the impact of a change on upstream and downstream systems, and the contracts between services - rather than simply confirming acceptance criteria from a user's seat. You will drive the full test lifecycle for your primary project (test plan → test design → execution → sign-off), and at the same time keep an overview of 1-2 additional projects so you can advise their testing teams and step in when delivery is at risk.
The role suits someone with very high ownership and a proactive mindset: someone who chases requirements before they are handed over, raises integration risks early, and is comfortable being the quality decision-maker for their project.
Key Responsibilities
Project ownership
Own the complete test lifecycle for one project: test strategy and test plan, test case design, test data preparation, execution, defect management, reporting, and formal sign-off.
Maintain an overall view of 1-2 additional projects: understand their requirements and integration landscape, advise and unblock their testing teams, and support hands-on execution when a project is critical or at risk (100% execution on those projects is not expected).
Participate in sprint planning and work closely with the Scrum team (developers, BAs, customer service, operations) to analyze requirements and provide test recommendations for feature, smoke, and regression testing.
Act as the quality point of contact for your project - proactively raise risks, gaps, and integration dependencies rather than waiting for them to be assigned.
Mentor and guide junior members of the test automation team, sharing best practices and knowledge.
System Integration Testing scope
Non-Functional testing - design and execute unhappy paths, and negative scenarios across integrated systems, downtime and feature flags combination matrix testing across multiple channels of platform, DB testing.
BC & FC testing - assess and cover the impact of a change on the systems before and after it in the business flow, so integration side effects are caught rather than discovered in production.
API testing - produce dedicated API test cases (not derived only from UI scenarios), and design scenario matrices that combine API response statuses, error conditions, and data variations to achieve meaningful coverage.
Regression testing - plan and execute regression cycles manually, as required by the project; keep the regression suite current as the integrated systems evolve.
Apply appropriate test techniques throughout: requirement analysis, risk-based testing, black-box techniques, exploratory testing, and non-UI testing.
Test automation
Address test automation needs in a methodical, detail-oriented manner, using strong analytical and problem-solving skills.
Automate functional, regression, and/or performance acceptance tests where automation adds value alongside the required manual coverage.
Take responsibility for growing end-to-end automated test coverage and for keeping the automation suite stable and maintainable.