Responsibilities include: defining and executing scalable BigCommerce architecture, leading technical discussions, developing headless commerce solutions using APIs, GraphQL, Webhooks, integrating with ERP, CRM, PIM, OMS, payment gateways, optimizing performance, security, and scalability, establishing best practices, and collaborating with UI/UX teams. Requirements: 8+ years in eCommerce development (3+ in BigCommerce), proficiency in BigCommerce Stencil, APIs, headless commerce, expertise in JavaScript, Node.js, React.js/Vue.js, experience with third-party integrations, CI/CD, cloud infrastructure, and knowledge of performance, caching, security.