Senior Staff Software Engineer

Summary

Join Upwork's Hybrid Workforce Solutions Team as a Staff Software Engineer and lead the design and development of our next-generation web architecture. You will play a pivotal role in defining how our platform supports modular, performant, and scalable frontend experiences, driving the adoption of federated app shell architecture and pioneering horizontal micro apps. This role requires architecting and building modular frontend infrastructure, leading the development of an app shell model, developing AI toolkit components, setting technical direction, and mentoring engineers. You will collaborate with various teams to align platform capabilities with user needs and evaluate and scale frameworks that align with emerging LLM agent SDKs. The position demands strong leadership, collaboration, and technical expertise in frontend development and web architecture.

Requirements

• 8+ years of experience in frontend development with deep knowledge of modern frameworks (React, Vue, Next.js, etc.) and native browser APIs
• Strong understanding of web architecture principles: security by design, server/client rendering paradigms, hydration techniques, micro frontends
• Experience designing for runtime UI composition, shared component governance, and telemetry/a11y/compliance hooks
• Deep knowledge of building for performance at scale: modular loading, edge delivery, multi-level caching, streaming responses
• Passion for AI-native patterns and agentic workflows; familiarity with LLM SDKs and AI UI concepts a plus
• Proven track record of leading architectural transitions in complex product ecosystems
• Excellent communication and collaboration skills, especially in cross-team roles

Responsibilities

• Architect and build modular frontend infrastructure with hybrid rendering (SSR, edge functions, client hydration) to support dynamic AI-native UIs
• Lead development of an app shell model to enable federated delivery of horizontal micro frontends across teams, with strong ownership boundaries and runtime flexibility
• Develop and evangelize AI toolkit components , enabling common interaction patterns (clarify, retry, fallback, tone) to be reused across the platform
• Set technical direction and collaborate with platform leads, design systems, and developer tooling teams to ensure consistency, governance, and rapid iteration support
• Evaluate and scale frameworks (e.g., React, Next.js) that align with emerging LLM agent SDKs and support agentic UI flows
• Mentor engineers and contribute to technical leadership across Product Engineering through architecture reviews, design discussions, and shared learning
• Collaborate cross-functionally with Product, Design, and Infrastructure teams to align platform capabilities with user-facing needs

Preferred Qualifications

• Hands-on work with observability pipelines, and build/deployment tooling
• Familiarity with widget-based delivery, embeddable apps, cross-context communication
• Prior experience in a high-scale consumer or enterprise SaaS environment
• Contributions to internal or open-source design systems or component libraries