Freelance Senior Test Engineer – Payments, API & Performance

Optimus Search; Bonn; Vor Ort; EUR 101.000 - 138.000; Vollzeit

Zusammenfassung

Optimus Search is seeking a Senior Test Engineer for a 12-month freelance engagement in Bonn, focusing on payments platforms, APIs and performance testing. The role covers technical testing of high-volume transactional applications, integrations, and CI/CD aligned processes within a complex payments ecosystem.

The candidate will implement system, integration and API tests, conduct load and resilience testing, and contribute to test automation while coordinating defect analysis with developers.

Qualifikationen

• Proven hands-on software testing and test engineering background.
• Experience with integration and E2E testing.
• API/REST testing experience.
• Load and performance testing experience.
• Experience with complex transactional systems; banking/fintech/payments a plus.
• Strong defect analysis and test documentation.

Aufgaben

• Design and execute technical test scenarios for payment applications
• Perform System, Integration, E2E and API testing
• Validate transaction flows across multiple applications and interfaces
• Design test cases, test data and test scenarios
• Perform REST API and service-level testing
• Conduct load, performance and resilience testing
• Analyze application behaviour and identify performance bottlenecks
• Test interfaces between payment platforms and downstream systems
• Execute regression and functional testing
• Support and expand test automation
• Perform detailed defect analysis and coordinate resolution with developers
• Support continuous testing within CI/CD environments
• Produce technical test documentation and test reports

Kenntnisse

API testing

Load testing

Performance testing

E2E testing

Defect analysis

Tools

Postman

JMeter

LoadRunner

Gatling

SQL

GitLab

Jobbeschreibung

Freelance Senior Test Engineer – Payments, API & Performance

12-Month Freelance Contract

Credit Card / Payments - Bonn

We are looking for an experienced Senior Test Engineer / Technical Test Consultant to join a major technology programme within the credit-card and payments industry.

The focus will be on technically testing high-volume transactional applications, APIs and integrations across a complex payments ecosystem.

Responsibilities

• Design and execute technical test scenarios for payment applications
• Perform System, Integration, E2E and API testing
• Validate transaction flows across multiple applications and interfaces
• Design test cases, test data and test scenarios
• Perform REST API and service-level testing
• Conduct load, performance and resilience testing
• Analyse application behaviour and identify performance bottlenecks
• Test interfaces between payment platforms and downstream systems
• Execute regression and functional testing
• Support and expand test automation
• Perform detailed defect analysis and coordinate resolution with developers
• Support continuous testing within CI/CD environments
• Produce technical test documentation and test reports

Technical Environment

• REST APIs / Postman
• JMeter / LoadRunner / Gatling
• SQL
• GitLab
• CI/CD / DevOps
• Microservices

Required Experience

• Strong hands-on software testing / test engineering background
• Integration and E2E testing experience
• API / REST testing
• Load and performance testing
• Experience with complex transactional systems
• Banking, fintech, credit-card or payments experience highly desirable
• Strong understanding of defect analysis and test documentation

Experience testing high-volume, business-critical financial transactions would be particularly relevant.

Contract: 12 months

Type: Freelance

Industry: Credit Cards / Payments / FinTech