Payment SDET

Are you passionate about building systems that prevent financial failures before they reach production? We’re looking for a Payment SDET to join Breeze, a Sequoia-backed fintech startup building the universal payment layer that unifies all currencies — fiat and crypto — so businesses and consumers can transact seamlessly.

In this role, you won’t be clicking buttons or writing manual test cases. Instead, you’ll build the reliability infrastructure that allows our Product Engineers to move fast without breaking critical financial logic. You’ll write code that tests code, designing simulation environments and automated frameworks that validate complex payment flows before every deployment.

This is a highly technical, engineering-driven role with deep impact on revenue, compliance, and customer trust.

• →Build and maintain a mock payment simulation server that mimics third-party providers such as WorldPay, Checkout.com, and Basis Theory.
  
  
• →Programmatically simulate complex edge cases, including network timeouts, soft declines, hard declines, retries, and 3DS authentication flows.
  
  
• →Design and own a robust automated regression testing framework for payment and financial workflows.
  
  
• →Validate complex state transitions across systems (e.g., retries, fallbacks, idempotency, and database consistency).
  
  
• →Generate and manage dynamic test data, including users, orders, and payment tokens, to eliminate flaky or stale test failures.
  
  
• →Integrate automated test suites into CI/CD pipelines and define strict gatekeeping rules for production deployments.
  
  
• →Partner closely with backend and product engineers to review feature designs and define test strategies before implementation.
  
  
• →Debug test failures and support engineers in identifying whether issues stem from product logic, infrastructure, or test systems.
  
  

• 2+ years of professional software engineering experience, with a strong focus on testing, automation, or backend systems.
  
  
• Strong programming skills in Python, Go, or Java, with experience writing production-quality code.
  
  
• Deep understanding of API testing, integration testing, and system-level validation (beyond unit tests).
  
  
• Experience with mocking and stubbing tools such as WireMock, Mountebank, Mockito, or similar frameworks.
  
  
• Familiarity with CI/CD pipelines (GitHub Actions, GitLab CI, Jenkins) and test gating strategies.
  
  
• Experience working with databases and validating data integrity using SQL.
  
  
• Strong debugging mindset — you enjoy breaking systems to understand how they fail.
  
  
• Excellent communication skills and the ability to work closely with product and engineering teams.
  
  
• Bonus: experience testing payments, fintech systems, or other highly regulated, stateful systems.