This position is listed on behalf of a partner company, who manages all applications and next steps. Our partner is looking for a Staff Fullstack Engineer (Ruby/Vue.js) Monetization Engineering: Purchase based in the United States. This is a Staff-level engineering opportunity focused on building and evolving the systems that power a modern, end-to-end purchase experience. You will work across frontend and backend technologies to create intuitive purchasing interfaces and reliable services that support transactions, billing, and customer relationship workflows. The role combines hands-on software development with technical leadership, architecture ownership, and mentorship across a high-impact product area. You will partner closely with Product, Design, Billing, Sales, Support, and Engineering teams to turn complex requirements into resilient and scalable solutions. Because your work directly influences revenue and involves sensitive customer and financial information, reliability, security, correctness, and safe delivery are critical. You’ll help unify purchasing experiences, improve self-service capabilities, and strengthen integrations with downstream systems. This is an ideal role for a senior engineer who wants to shape technical direction while remaining deeply involved in building and operating production software.