Owns Shopify checkout and post-purchase extensions, experimentation reporting, and revenue-critical APIs across PHP, TypeScript, MySQL, BigQuery, and Google Cloud. Designs secure REST services, investigates production issues, participates in on-call, and maintains unit and end-to-end testing without a separate QA handoff. The role requires Staff-level technical ownership, system-wide architectural judgment, AI-assisted development, mentoring, and collaboration in a remote, high-autonomy environment.