Engineer, SDET/Automation [T500-30497]

• Engineer, SDET/Automation

Job Overview

Are you ready to join the Un-carrier movement The T-Mobile FinTech Platform team is seeking a Software Development Engineer in Test (SDET) with a focus on automation to build and maintain automated testing solutions that improve product quality, accelerate delivery, and support the reliability of digital banking, payments, account management, card services, and financial transaction processing capabilities. You will collaborate with software engineering, product, architecture, quality engineering, operations, security, and partner teams to validate backend APIs, microservices, integrations, and distributed workflows across internal T-Mobile systems and external banking and financial technology providers. This role emphasizes transaction accuracy, data integrity, secure handling of sensitive financial information, and automation-first quality practices throughout the software development lifecycle. This is a hands-on quality engineering role for an engineer with 3+ years of relevant testing or automation experience. Prior FinTech experience is preferred but not required. We encourage innovation, continuous learning,

collaboration, and operational excellence in the Un-carrier way.

Job Responsibilities

• Design, develop, execute, and maintain automated functional, integration, regression, API, and end-to-end tests for FinTech backend services and microservices.
• Build and enhance reusable automation frameworks using Java, Python, or JavaScript and appropriate tools such as Rest Assured, Selenium, TestNG, JUnit, or Cucumber .
• Validate REST APIs, service contracts, downstream integrations, and transaction workflows spanning internal platforms and external banking or payment partners.
• Test account, payment, card, and transaction scenarios, including validation, error handling, retries, idempotency, data consistency, and reconciliation where applicable.
• Integrate automated test suites and quality gates into CI/CD pipelines to enable fast feedback and reliable releases.
• Collaborate with engineering and product teams to define test plans, acceptance criteria, risk-based coverage, and quality strategies.
• Create and manage test data, mock services, and automated environment checks while protecting sensitive customer and financial information.
• Validate relational and NoSQL data, asynchronous messages, and event-driven processing where applicable.
• Analyze failures, reproduce defects, troubleshoot logs and service behavior, and partner with developers on fixes and regression prevention.
• Participate in Agile ceremonies, peer reviews, design discussions, and shift-left testing activities.
• Support observability and monitoring validation using application logs, metrics, and traces, and contribute to release and production-readiness testing.
• Document test scenarios, automation standards, API validation approaches, test evidence, and operating procedures.
• Continuously improve test reliability, coverage, maintainability, execution speed, and engineering practices.
• Also responsible for other duties/projects as assigned by business management as needed.

Education and Work Experience

• Bachelor’s degree in computer science, Software Engineering, Engineering, or related technical discipline, or equivalent relevant experience consistent with company policy. (Required)
• 3+ years of relevant experience in software testing, test automation, software development, or quality engineering.

Required Qualifications

• Hands-on experience programming automated tests in Java, Python, or JavaScript .
• Experience with automation frameworks such as Rest Assured , Selenium , TestNG/JUnit , Cucumber, or comparable tools.
• testing REST APIs, microservices, and system integrations.
• Knowledge of SQL queries, database validation, and test data management fundamentals.
• Experience integrating automated tests into CI/CD pipelines and working with Git-based development workflows.
• Understanding of functional, integration, regression, and end-to-end testing methodologies.
• Ability to troubleshoot failures, analyze logs, isolate defects, and communicate technical findings. Understanding secure test practices for sensitive customers, account, and transaction data.
• Experience working with Agile teams and tools such as JIRA and Confluence.
• Effective communication and collaboration across engineering, product, and operations teams.

Preferred Qualifications

• Experience testing digital banking, payments, card services, account servicing, or other transaction-oriented systems.
• Experience with external banking partner APIs, payment processors, or financial technology integrations.
• Familiarity with AWS, Docker, Kubernetes, and cloud-native test environments.
• Experience testing event-driven architecture using Kafka, RabbitMQ, or other messaging platforms .
• Knowledge of performance testing tools such as JMeter, k6, or Gatling .
• Experience with service virtualization, mock servers, contract testing, or API schema validation.
• Familiarity with Splunk, Grafana, Dynatrace, CloudWatch, or other observability tools .
• Exposure to Terraform, Helm, or other infrastructure and deployment tooling.
• Experience with Cypress/ Playwright , or other frontend testing frameworks.
• Familiarity with SonarQube or code coverage and quality analysis tools.
• Understanding of encryption, authentication, authorization, auditability, PCI-related controls, or testing in regulated environments.

Knowledge, Skills, and Abilities

• Test automation engineering and maintainable framework design
• API and microservices testing
• Java, Python, or JavaScript scripting
• SQL and data validation
• CI/CD and automated quality gates
• Defect analysis, debugging, and problem-solving
• Secure handling of sensitive financial test data
• Technical documentation and cross-functional collaboration
• Customer-focused quality engineering and continuous improvement