Senior Full-Stack Engineer, Platform

Location: New York, New York  Experience: 5+ years  Type: Full-timeAbout HandledHandled is the world's most advanced commerce automation platform, powering the daily operations of hundreds of ecommerce brands and their 3PLs fulfilling 100,000+ orders a day. Handled executes the manual work behind every order—resolving shipment issues, processing returns, resolving support tickets, and adjusting invoices—so e-commerce brands and 3PLs can scale volume without scaling headcount.About the RoleWe're looking for an exceptional Senior Full Stack Platform Engineer to take ownership of our automation and integration infrastructure that powers custom workflows for e-commerce and logistics operations. You'll be stepping into a foundational role, maintaining and evolving a novel automation platform and integration node generator that we've built from the ground up.This is a high-impact position where you'll own the entire stack—from backend infrastructure to user-facing interfaces—building and maintaining the critical systems that power our platform.What You'll OwnFull Stack Platform Development- Maintain and evolve our custom workflow automation platform- Build intuitive frontend interfaces for workflow management, data visualization, and admin tools- Develop mobile app experiences (React Native or similar frameworks)- Create drag-and-drop interfaces and self-serve automation toolsBackend & Integration Infrastructure- Own the integration node generator that accelerates third-party system connections- Build and maintain integrations with e-commerce and logistics platforms- Create authentication layers and data synchronization workflows- Design and implement APIs for internal and external consumptionDevOps & Platform Reliability- Own backend infrastructure, deployment pipelines, and system architecture- Ensure platform stability and performance under production workloads- Implement monitoring, alerting, and observability across the stackProduct Development- Build complete features end-to-end across multiple product lines (Returns, Tracking, Analytics)- Iterate on UX/UI improvements based on customer feedback- Create data visualization tools and dashboards using tools like MetabaseAI-Enhanced Development- Leverage LLMs to improve development velocity and platform capabilities- Explore opportunities to enhance platform intelligence and user experienceRequired ExperienceFull Stack Mastery- 4+ years of full stack software engineering experience- Expert-level proficiency in Ruby on Rails (backend)- Strong React skills with ability to build production-quality user interfaces- Experience building mobile applications (React Native, Flutter, or native iOS/Android)- Proven ability to own features from database to UI independentlyFrontend Excellence- Strong understanding of modern frontend architecture and state management- Experience building complex interactive UIs (drag-and-drop, real-time updates, data visualizations)- Solid grasp of UX/UI principles and ability to implement polished user experiences- Comfortable with CSS/styling frameworks and responsive designBackend & Platform Engineering- Deep backend engineering fundamentals and API design expertise- Experience building developer-facing platforms, workflow automation tools, or integration frameworks- Strong understanding of distributed systems, data synchronization, and webhooks- Solid DevOps experience (deployment automation, infrastructure management)Domain Knowledge- Strong understanding of e-commerce and logistics operations- Familiarity with the challenges of multi-tenant SaaS in commerceAI Literacy- Practical experience leveraging LLMs in development workflows- Comfort using AI to accelerate coding, debugging, and problem-solving across the stack- Interest in exploring AI-enhanced platform capabilitiesNice to Have- Experience with analytics platforms, ETL pipelines, data warehousing, and BI tools- Background in returns management, fulfillment, or 3PL operations- Contributions to open-source workflow automation or integration projects- Design skills or experience working closely with designers- Experience working in early-stage startups or as a founding engineerWhat Makes This Role UniqueTrue Full Stack Ownership: You'll own features completely—from database schema to API design to the final pixel on screen. No "throw it over the wall" to another team.Broad Product Surface Area: You'll work across multiple products (Returns management, Tracking & Alerts, Analytics dashboards) giving you diverse technical challenges.High Autonomy: You'll own the entire platform with minimal oversight. We need someone who can make independent decisions on both technical architecture and user experience.Foundational Impact: This isn't maintaining legacy code—you're evolving a platform that's the foundation for everything we build. Your decisions will shape the company's future.Complex Problem Space: You'll tackle the challenge of building products in an industry with high combinatorial complexity. This requires creative problem-solving beyond typical SaaS development.The Startup RealityThis is a startup role. We're building something ambitious from the ground up, and that comes with unique demands and opportunities:Pace and intensity: You'll move fast, ship often, and adapt quickly. Expect to wear multiple hats and tackle problems outside your traditional scope.Ambiguity and ownership: There won't always be a clear playbook. You'll need to be comfortable making decisions with incomplete information and owning the outcomes.Resource constraints: You'll need to be scrappy and strategic, prioritizing ruthlessly and finding creative solutions with limited resources.High stakes: Your work directly impacts our customers' operations and our company's trajectory. The margin for error is small, but the opportunity for impact is massive.Evolving priorities: Product direction and customer needs will shift. Flexibility and resilience are essentialIf you thrive in structured, process-heavy environments with specialized roles, this might not be the right fit. But if you're energized by building something from scratch, solving hard problems with autonomy, and seeing your work directly move the needle, you'll love it here.Our StackBackend- Ruby on RailsFrontend- React (web applications)- React Native or similar (mobile apps)Infrastructure & Tools- Analytics and BI platforms- ETL pipelines and data warehousing- AI/LLM-assisted development workflowsWhat Success Looks LikeFirst 90 days:- Deep understanding of platform architecture across frontend and backend- Shipped end-to-end improvements to product UX and platform reliability6 months:- Ownership of full stack roadmap- Shipped major features independently from concept to production- Improved developer experience and reduced build times further1 year:- Platform scaled to support multiple product lines with polished UIs- Architectural improvements that unlock new capabilities- Mentoring potential future team members---Why Join Us:You'll have complete ownership over the entire stack powering the world's most advanced commerce automation platform. If you thrive on building complete products end-to-end, solving complex integration challenges, and working with emerging AI technologies, this role offers significant growth and impact. No more context switching between teams—you build it, you own it, you ship it.CompensationBase salary: $180,000 – $220,000 USD, plus equity.