Mid-Level QA Engineer

SLEM Technologies; United States; Remote; USD 65,000 - 95,000; Full time

Job summary

SLEM Technologies in the United States is seeking a skilled QA tester to validate payment applications and checkout journeys across MPGS and Visa Cybersource. You will collaborate with developers and senior QA engineers to ensure transaction accuracy and data protection for customer funds.

You will run manual and automated tests in sandbox environments, verify authorisation, capture, refunds, 3-D Secure, tokenisation, and reconciliation, and contribute to regression suites using SQL and the

Qualifications

• 2+ years of professional software testing experience, fintech or payments.
• Hands-on testing with MPGS and Visa Cybersource.
• Experience testing payment APIs and checkout journeys, incl. declines.
• Understanding of authorisation, capture, refunds, 3-D Secure, tokenisation.
• Basic SQL and familiarity with an automation framework.
• Awareness of PCI DSS and secure handling of test data.

Responsibilities

• Run manual and automated tests against sandbox integrations for both payment gateways.
• Verify successful payments, declines, 3-D Secure challenges, tokenisation, captures, refunds.
• Test duplicate submissions, timeouts, retries, gateway notifications, and status updates.
• Use SQL and API checks to verify amounts, currencies, ledger records, and reconciliation.
• Write clear, sanitised defect reports and validate fixes across flows.
• Maintain regression tests and use approved credentials and synthetic card data.

Skills

Software testing

Fintech

Payment processing

API testing

SQL

PCI DSS

Automation framework

Collaboration

Tools

MPGS

Visa Cybersource

Job description

Role overview

Test payment applications and APIs integrated with both MPGS and Visa Cybersource. Working with developers and senior QA engineers, you will validate checkout, payment processing, refunds, and reconciliation, and provide clear evidence that helps protect customer funds and financial data accuracy.

Responsibilities

• Run manual and automated tests against sandbox integrations for both payment gateways.
• Check successful payments, declines, 3-D Secure challenges, tokenisation, captures, voids, and refunds.
• Exercise duplicate submissions, timeouts, retries, gateway notifications, and transaction-status updates.
• Use SQL and API checks to verify amounts, currencies, ledger records, and reconciliation results.
• Write reproducible defect reports with sanitised evidence, then verify fixes across affected flows.
• Maintain regression tests and use approved credentials and synthetic card data.

Requirements

• At least two years of professional software testing experience, including fintech or payment-processing products.
• Hands-on testing experience with both MPGS and Visa Cybersource.
• Practical experience testing payment APIs and checkout journeys, including declines and failure scenarios.
• Understanding of authorisation, capture, refunds, 3-D Secure, tokenisation, and reconciliation.
• Familiarity with an automation framework and basic SQL.
• Awareness of PCI DSS and secure handling of payment test data, with clear defect reporting.
• Ability to collaborate with engineers and product teams.

Nice to have

• Experience maintaining payment automation in CI.
• Familiarity with settlement reports, chargeback workflows, or fraud scenarios.