Senior Software Engineer

About Extend: Extend is a premier, hyper-growth post-purchase technology pioneer, e-commerce platform innovator, and AI-driven infrastructure leader on an intensive mission to revolutionize retail interactions for merchants and consumers alike. By delivering a comprehensive merchant stack that unifies automated customer service processing, seamless return/exchange frameworks, end-to-end automated fulfillment tracks, and advanced fraud detection modules, Extend drives continuous brand loyalty and margin expansion. Trusted by more than 1,000 leading merchant partners across diverse apparel, cosmetics, electronics, and automotive components sectors, Extend is backed by the industry’s most prominent venture investors to scale cutting-edge retail financial systems globally.

Position Overview

We are seeking a highly sophisticated, systems-minded Senior Software Engineer II to join our core Extend Fulfillments team in a full-time remote capacity within the United States. In this highly technical leadership seat, you will claim absolute end-to-end ownership over designing, scaling, and deploying the distributed software systems that directly influence how the world’s largest brick-and-mortar and digital marketplaces fulfill customer orders. Moving far beyond boilerplate frontend configurations, you will operate cross-functionally across ambiguous, cross-system environments to deliver event-driven, AI-native production features where microservices drive multi-million dollar money movements. This high-agency role demands an expert-tier developer who brings deep hands-on serverless cloud experience, handles advanced data modeling and context engineering, and can habits-code team-wide improvements that outlast any single deployment cycle.

Key Responsibilities

• Fulfillment Feature Engineering: Design, build, and optimize scalable full-stack features within the core Extend Fulfillments product loop, ensuring high availability, fault tolerance, and system maintainability.
• NodeJS Server-Side Development: Model, secure, and maintain high-concurrency event-driven APIs and serverless microservices natively utilizing Node.js and TypeScript backend routing frameworks.
• Interactive Interface Programming: Code fluid, intuitive, and responsive client-facing components and transactional dashboards using React and modern state management principles.
• AI/LLM Production Integration: Own the design, runtime implementation, and automated testing of production-grade AI/agentic features, leveraging deep context engineering to support sound machine decisioning loops.
• Event-Driven Schema Modeling: Maintain robust data models and strict backwards-compatible API structures, especially across distributed ledger segments where real-time events handle transactional money movements.
• System Observability Advocacy: Drive proactive technical investments across shared repositories, architecting platform logging metrics, custom alerting rules, and code refactors to streamline core system velocity.
• Team-Wide Technical Mentorship: Coach and lift developers across multiple levels, conducting granular code reviews, architectural design collaborations, and technical pairing sessions to codify robust practices.
• Cross-Functional Alignment Loops: Communicate technical plans smoothly across distributed product owners, UI/UX design squads, and operations business stakeholders to tie software features straight to target revenue outcomes.

Required Skills & Qualifications

• 8+ years of verified professional history running full-stack software application development, backend systems engineering, or large-scale cloud-native architecture delivery.
• Proven, hands-on operational experience building distributed, highly available applications natively inside serverless cloud-native structures.
• Demonstrated commercial background writing, testing, and shipping live production-grade AI and Large Language Model (LLM) features.
• Expert-tier, authoritative programming literacy in TypeScript, Node.js, and React application environments.
• Exceptional command over transactional API design mechanics, database modeling principles, and maintaining absolute backwards-compatibility across event streams.
• Proven background influencing engineering decisions beyond your immediate team, distilling complex technical constraints into clear, data-driven advice for corporate leadership.
• Location Context: Full-time remote-first parameters open exclusively to qualified full-stack engineering leads permanently based and legally authorized to execute anywhere within the United States.

Preferred Strategic Indicators (Nice to Have)

• Prior experience operating within e-commerce infrastructure, post-purchase retail technologies, digital fulfillment grids, or payment clearing networks.
• Active personal habit of utilizing next-generation AI developer tooling to safely accelerate code compilation throughput and code verification cycles.
• Familiarity navigating relational database clusters, non-relational storage layers, or event brokers such as Kafka or AWS EventBridge.

What We Offer

• Competitive Salaried Compensation: An attractive, capability-calibrated annual base salary package mapped precisely between $171,000 – $198,000 USD, tailored transparently to evaluate your senior domain background.
• The exceptional professional canvas to directly program, own, and advance the fulfillment architectures supporting thousands of global retail brands.
• Profound work-from-home remote parameters offering high lifestyle autonomy, flexible schedules, and zero physical office commute drag inside the US.
• Immediate access to corporate equity options, giving you a valuable stock stake in a rapidly scaling, heavily backed tech leader.
• Comprehensive health care provisions, including 100% employer-covered medical, dental, and vision protection insurance structures for the employee.
• Access to a stable corporate 401(k) retirement plan supplemented by expert financial guidance frameworks powered directly by Morgan Stanley.
• Generous, highly flexible paid time off structures designed to prioritize continuous personal well-being and a highly supportive startup culture.