- Experience writing complex queries using:
- Joins
- Aggregations
- Subqueries
- Window Functions
- Reconciliation Queries
- Data Comparison Techniques
Job Type: Permanent
Location: Letterkenny GDC, Co. Donegal (Hybrid – minimum 3 days onsite per week)
Do you have strong experience in ETL and data testing, with the ability to validate complex data flows and integrations?
Do you bring a solid QA background, with experience in automation testing and defect investigation across enterprise applications?
Are you an analytical problem solver who enjoys investigating data issues, identifying risks early, and helping teams deliver quality solutions with confidence?
Make your mark at TCS as an ETL/Data Test Engineer.
Join a global tech leader right here in Donegal. With over 850 employees and a state-of-the‑art global delivery centre, we’re proud to offer world‑class career opportunities without having to leave the Northwest. Recognised as Workplace of the Year by the Letterkenny Chamber, we foster a culture of continuous learning, innovation, and respect. Our people are at the heart of everything we do – collaborating across teams, geographies, and disciplines to drive real change for clients around the world. Be part of something global, grounded in Donegal.
TCS is a purpose‑led transformation company, built on belief. We do not just help businesses to transform through technology. We support them in making a meaningful difference to the people and communities they serve - our clients include some of the biggest brands in the UK and worldwide. For you, it means more to make an impact that matters, through challenging projects which demand ambitious innovation and thought leadership.
- Join a leading global IT services organisation.
- Be part of an exciting team where you will be challenged every day.
- Gain exposure to innovative technology.
The Role
We are seeking an experienced ETL/Data Test Engineer with a strong background in data testing and quality assurance. The ideal candidate will have proven experience in ETL testing, data migration testing, data reconciliation testing, SQL validation, batch processing validation, and Automation testing. This is a hands‑on role for that requires a detail‑oriented professional who can analyse complex data flows, investigate issues, perform root cause analysis, and ensure the accuracy and integrity of data across multiple systems.
You will help shape the testing approach, review requirements, understand business context, validatedata and integrations, and clearly communicate quality risks before release. The role suits someone proactive,practicaland confident, with the ability to work across different priorities while keeping quality and delivery in focus.
The successful candidate should be comfortable working in a fast‑paced Agile environment and possess excellent communication, stakeholder management, and analytical skills.
Key Responsibilities:
- Own QA activities for assigned work from requirement review through to release readiness.
- Review user stories and requirements to understand business context, risks,dependenciesand downstream impacts.
- Design and execute clear test scenarios covering functional, integration, regression,dataand edge-case testing.
- Ask questions,validateassumptionsand raise risks early when requirements, test coverage,environmentsor timelines are unclear.
- Clearly communicate test progress, defects, blockers, releaseconfidenceand any remaining quality risks.
- Take part in Agile ceremonies, including refinement, sprint planning, stand-ups, defecttriageand release discussions.
- Support colleagues through knowledge sharing, constructivefeedbackand a strong team-first approach.
- Perform end-to-end ETL and data testing activities.
- Validate source-to-target mappings, transformation rules, and business requirements.
- Execute data migration, data reconciliation, and data validation testing.
- Verify data accuracy, completeness, consistency, and integrity across multiple systems.
- Perform backend database testing and large-scale data analysis.
- Analyse files including CSV, TXT, XML, and JSON for data validation purposes.
- Write and execute complex SQL queries for backend validation and reconciliation.
- Monitor and validate batch-processing activities and scheduled jobs.
- Analyse job failures and perform detailed root cause investigations.
- Review and understand Python-based scripts used in data-processing workflows.
- Work in Linux/Unix environments to analyse logs and troubleshoot issues.
- Execute automated tests using existing Java and Python-based frameworks.
Your Profile
Essential skills/knowledge/experience:
- 5+ years of experience in software testing, qualityengineeringor a similar technical QA role.
- Strong analytical and troubleshooting skills with experience in system validation, defect analysis, root cause identification, and cross-system data reconciliation.
- Strong understanding of SDLC, Agile delivery,Jiraand Confluence.
- Good critical thinking skills, with the ability to consider broader business impact, edgecasesand production risk.
- Confident communicator who can ask clear questions, challenge assumptions professionally and raise concerns early.
- Strong ownership,organisationandprioritisationskills, especially when managing multiple work items or business areas.
- Willingness to use AI-enabled tools responsibly to improve productivity, analysis,documentationor testing effectiveness.
- Hands-on experience with test automation, ideally using Selenium and automation frameworks.
Required Technical Skills
ETL & Data Testing
- Strong and recent ETL/Data Testing experience.
- Proven experience in:
- ETL Testing
- Data Validation Testing
- Data Migration Testing
- Data Reconciliation Testing
- Source-to-Target Validation
- Data Quality Testing
- Data Recon Automation Testing
- Experience validating large and complex datasets.
- Strong understanding of data lifecycle, data transformations, and batch processing.
SQL & Database Testing
- Advanced SQL skills and data analysis capability.
- Experience writing complex queries using:
- Joins
- Aggregations
- Subqueries
- Window Functions
- Reconciliation Queries
- Experience working with SQL Server, PostgreSQL, MsSQL or Oracle.
- Strong database testing and backend validation experience.
Data Analysis & Excel
- Advanced Microsoft Excel skills.
- Experience using:
- Pivot Tables
- VLOOKUP/XLOOKUP
- Conditional Formatting
- Data Comparison Techniques
- Data Reconciliation Methods
- Ability to analyse large datasets and identify anomalies, trends, and discrepancies.
- Ability to use text/data compare tools like Beyond Compare.
Linux & Job Monitoring
- Strong Linux/Unix knowledge.
- Experience analysing logs and troubleshooting batch-processing issues.
- Experience working with Autosys or similar enterprise scheduling tools.
- Ability to investigate job failures and perform root cause analysis.
Automation Knowledge (Preferred)
- Experience executing and troubleshooting automated test suites.
- Exposure to Java, Selenium, TestNG, Python, PyTest
- Ability to understand existing automation frameworks.
- Ability to review and understand Python scripts used within testing and data-processing workflows.
Desirable skills/knowledge/experience:
- Experience in Financial Services, Asset Management, Banking, CapitalMarketsor another data-driven enterprise environment.
- Previousexperience as a Senior QA, QA Lead, AutomationLeador mentor to other testers.
- Experience testing data feeds, reporting processes, audit trails, marketdataor complex downstream data processes.
- Exposure to cloud platforms such as AWS or Azure.
- Experience with CI/CD, DevOpspracticesor continuous testing approaches.
- Relevant certifications such as ISTQB, Agile/Scrum, AWS,Azureor automation-related certifications.
Rewards & Benefits
TCS is consistently voted a Top Employer in the UK and globally. Our competitive salary packages feature pension, health care, life assurance, laptop, phone, access to extensive training resources and discounts within the larger Tata network.
We offer health & wellness initiatives and sports events; we are the proud sponsor of the London Marathon.
Diversity, Inclusion and Wellbeing
Tata Consultancy Services UK&I is committed to meeting the accessibility needs of all individuals in accordance with the UK Equality Act 2010 and the UK Human Rights Act 1998.
We welcome and embrace diversity in race, nationality, ethnicity, disability, neurodiversity, gender identity, age, physical ability, gender reassignment, sexual orientation. We are a disability inclusive employer and encourage disabled people to apply for this role.
As a Disability Confident Employer, we offer an interview to applicants with disabilities or long‑term conditions who meet the minimum criteria for the role. Please email us [email protected] if you would like to opt in.