Senior Test Automation Engineer / SDET (Remote)

Role overview

Senior Test Automation Engineer / SDET (Remote). You will build the test infrastructure for a crypto payment platform (custody, AML/screening, and stablecoin settlement). This is a horizontal role supporting multiple development squads across both an existing platform and a new greenfield platform.

Responsibilities

• Design and build stateful mocks and simulators of third-party vendor APIs (custody, KYC/KYB, screening providers) for current and new platforms.
• Implement contract tests scheduled to run against real vendor sandboxes to catch unannounced API changes early.
• Create test data and environment tooling, including one-command environments with meaningful state.
• Own the CI test pipeline: fast PR feedback, heavier nightly integration suites, pre-release suites, and test parallelization.
• Eliminate flaky tests via quarantine, statistics, and root-cause analysis.
• Build test-writing scaffolding (helper libraries, fixtures, object builders) and documented test patterns (as templates for AI-assisted test generation).
• Coach engineers through reviews and pairing so each team can maintain quality in their own code.
• Add production-adjacent checks such as post-deploy smoke tests, synthetic transactions, and automated verification before traffic cutover.

Required qualifications

• 5+ years as a software engineer with substantial test-infrastructure ownership (SDET/platform engineering/backend with heavy testing responsibility).
• Strong TypeScript for backend services and test automation.
• Experience building test frameworks/harnesses from scratch (not just writing tests on top of existing frameworks).
• Hands-on Playwright.
• CI/CD test design experience (example: GitLab CI), including parallelization and selective test execution.
• Ability to API test and mock/stub third-party services.
• Daily hands-on experience with AI coding tools, with critical review of AI-generated code.
• Crypto experience is optional, but learning custody/stablecoin settlement/screening flows is mandatory.
• High agency with comfort operating without daily supervision.
• Strong written and verbal communication in English.

Preferred experience

• Fintech/payments/crypto domain expertise; understanding money-flow testing (idempotency, reconciliation, state machines).
• Contract testing tooling such as Pact (or similar).
• Performance/load testing.
• Experience in regulated environments (e.g., financial services or healthcare).
• Test management tools such as TestRail.

Reporting

Reports to the Engineering Manager and aligns testing strategy with the QA Lead.

Contract & remote details

• Independent contractor role.
• Remote: EU, USA, Argentina, Brazil.
• Requires a minimum of 4 hours daily overlap with Central European working hours.