Automation Tester - Data Pipelines (ETL)

Location: Stevenage, UK

Job Type: Contract (6 months)
Work Model: Hybrid (3 days per week onsite)
Rate: Competitive Market Rates

The Role

We are looking for an experienced Automation Tester - Data Pipelines (ETL) to lead quality engineering for business-critical data pipelines.

This is a greenfield opportunity where you will define and build the testing strategy from the ground up, creating scalable automation frameworks for validating ETL pipelines, APIs, Excel reports, and XML outputs. Working closely with data engineers, you will ensure data accuracy, integrity, and reliability while embedding automated testing into CI/CD pipelines.

Key Responsibilities

• Define and own the testing strategy for ETL/data pipelines.
• Design and develop scalable automation frameworks using Python and Pytest.
• Create SQL-based validation scripts for reconciliation, business rules, duplicate detection, null checks, and data integrity.
• Automate validation of Excel outputs using Pandas and OpenPyXL.
• Validate XML outputs using lxml and xmlschema, including schema and business rule validation.
• Design and automate API testing using Postman and Newman.
• Integrate automated testing into GitHub Actions to support CI/CD quality gates.
• Produce clear test reporting, logging, and defect analysis to support rapid issue resolution.
• Collaborate closely with data engineers to improve data quality and testability.
• Mentor junior QA team members and promote testing best practices.

Essential Skills & Experience

• Proven experience testing ETL/ELT or enterprise data pipeline solutions.
• Strong SQL skills for complex data validation, reconciliation, and troubleshooting.
• Hands-on experience building automation frameworks using Python and Pytest.
• Experience using Pandas and OpenPyXL for validating Excel-based outputs.
• Experience validating XML using lxml and xmlschema.
• Strong API testing experience using Postman and Newman.
• Experience implementing automated testing within GitHub Actions or similar CI/CD platforms.
• Familiarity with Databricks or similar cloud-based data processing platforms.
• Strong understanding of data quality principles, including transformation validation, reconciliation, and data integrity.
• Experience establishing QA processes or leading data testing initiatives.

Desirable Skills

• Experience working with cloud-based data platforms and modern data stacks.
• Knowledge of data quality tools such as Great Expectations.
• Experience with orchestration tools such as Apache Airflow or Azure Data Factory (ADF).
• Experience with performance and large-volume data testing.
• Experience validating data across ETL pipelines, APIs, Excel, and XML outputs.
• Previous experience establishing or scaling QA practices within enterprise data environments.

What You'll Bring

You are a proactive Automation Tester with a passion for data quality and test automation. You enjoy solving complex data validation challenges, collaborating with engineering teams, and building robust testing frameworks that improve software quality and delivery confidence. You thrive in environments where you can take ownership, influence best practices, and make a measurable impact.