Sr. ETL Tester

Job Title : ETL Tester (SQL / Data-Warehouse / Data Integration)

Location : Singapore

Role Overview

We are looking for a meticulous and technically competent ETL Tester whose primary responsibility is to ensure data accuracy, integrity, and completeness across the ETL / data migration / data integration pipelines. The candidate will work closely with data engineers, business analysts, and stakeholders to validate that data extraction, transformation, and loading processes meet business requirements and quality standards.

Key Responsibilities

• Review and study source system specifications, data mappings (source → staging → transformation → target), functional requirements, metadata definitions, and business rules.
• Design, develop, and maintain comprehensive ETL test cases, scenarios, and test data, including edge cases, negative, null, invalid datatypes etc.
• Execute manual ETL testing: data extraction, data transformation, data loading, reconciliation between source and target systems.
• Use SQL scripts/queries extensively to validate data at each stage (source, staging, intermediate, target). Check for transformations, aggregations, filters, joins etc.
• Verify record counts, data types, data truncation, null/unique constraints, referential integrity, and key business rules.
• Perform regression testing for ETL processes after fixes or enhancements.
• Identify, document, track, and manage defects/issues. Provide clear steps to reproduce, expected vs actual results, logs/screenshots if applicable.
• Collaborate with data engineers to understand the ETL workflows, transformations, the scheduling of jobs, error handling/falls-backs.
• Participate in test planning, estimation, risk analysis; report test status, issues and risks to management.
• Assist with UAT (User Acceptance Testing) by stakeholders, ensuring data meets business needs.
• Maintain test artifacts: test plans, traceability matrices, test data sets, execution logs, reports.
• (Optional / depending on role) Automate portions of ETL testing (e.g., using SQL scripts, Python, or ETL testing tools like QuerySurge, Informatica test tools etc.).

Required Qualifications & Skills

• Bachelor's degree in Computer Science / Information Technology / Data Science / equivalent, or relevant experience.
• Experience: typically 3-7 years ETL / Data Warehouse Testing experience (can be adjusted based on level: junior / senior).
• Strong proficiency in SQL scripting: writing complex queries for data validation across multiple tables, joins, subqueries, aggregations, window functions, etc.
• Solid understanding of data warehousing concepts: dimensional modeling (star/snowflake schema), OLAP vs OLTP, fact and dimension tables.
• Experience with ETL tools / frameworks (e.g., Informatica, Talend, DataStage, SSIS) is a plus.
• Familiarity with databases such as Oracle, SQL Server, Teradata, PostgreSQL, MySQL, or cloud data warehouses (Snowflake, Redshift, BigQuery) depending on tech stack.
• Strong analytical & problem solving skills; attention to detail.
• Good understanding of software testing life cycle (STLC) and data testing methodologies.
• Experience with test management / defect tracking tools (e.g., JIRA, ALM, Bugzilla).
• Good communication skills, both verbal & written; ability to liaise between technical & non-technical stakeholders.

Preferred / Nice-to-Have

• Experience in data quality metrics, data profiling tools or techniques.
• Exposure to automation in ETL testing: scripting in Python, Shell, or use of tools to automate SQL-based test validations.
• Familiar with Big Data ecosystems: Hadoop, Spark, Hive etc.
• Cloud experience: AWS, Azure, GCP—especially with data services (e.g. ADF, Glue, BigQuery, Redshift etc.).
• Prior experience in relevant domain(s): Finance / Banking, Insurance, Healthcare, Retail etc.
• Knowledge of scheduling tools / workflows (e.g. Control-M, Cron) for ETL job orchestration.

Senior / Lead-Level Additions (if you need for Senior Role)

• Lead and mentor junior testers; review peer test cases / scripts.
• Drive improvement in testing processes and practices (e.g., improve test coverage, reduce defect leakage, optimize test execution times).
• Engage in performance or scalability testing of ETL / data pipelines.
• Ensure data governance, data security, compliance standards are met (especially for sensitive data, PII etc.).
• Collaborate in CI/CD / DevOps pipelines if ETL jobs are integrated in deployment.

Job Types: Full-time, Contract

Contract length: 12 months

Pay: $3, $9,805.89 per month