Staff Product Engineer - Frontend/Fullstack

Harnham; San Leandro (CA); Hybrid; USD 180,000 - 240,000; Full time

Job summary

Harnham is seeking a Senior Staff Product Engineer with a strong frontend background to own major initiatives across the engineering lifecycle. You will build sophisticated web applications, develop services and APIs, and collaborate with product and design to translate ambiguous requirements into robust software experiences.

You will drive architectural decisions, incorporate AI capabilities, and lead by example while mentoring engineers and partnering with cross-functional teams to deliver

Qualifications

• Extensive experience building and scaling complex software products.
• Strong frontend architecture experience with component systems and state management.
• Experience delivering AI-enabled features and integrating LLM capabilities.

Responsibilities

• Build sophisticated web applications with emphasis on usability, responsiveness, and frontend architecture.
• Develop application services and APIs supporting data-driven product functionality.
• Collaborate with product and design to translate unclear requirements into solid software.

Skills

Frontend architecture

Python backend

Full-stack development

API design

Technical leadership

Mentoring

Tools

Web frameworks

Job description

Senior Staff Product Engineer — Full Stack / Frontend Focus

Location: East Bay, CA

Work Arrangement: Hybrid

A rapidly evolving technology organization is expanding its engineering team to build sophisticated software products incorporating modern AI capabilities.

We’re looking for a highly experienced Senior Staff Product Engineer with a strong frontend background and the ability to operate across the full application stack.

What You’ll Own

• Build sophisticated web applications with an emphasis on usability, responsiveness, maintainability, and frontend architecture.
• Develop application services and APIs supporting complex, data-driven product functionality.
• Work closely with product and design partners to turn ambiguous requirements into well-engineered software experiences.
• Incorporate emerging AI capabilities into production applications, including natural-language interfaces, intelligent discovery, recommendations, summarization, and automated workflows.
• Own major initiatives throughout the engineering lifecycle — from technical discovery and architecture through implementation, launch, and continuous improvement.
• Establish scalable frontend patterns, shared components, and engineering practices that improve consistency and development velocity.
• Collaborate with engineers across AI, data, infrastructure, and platform teams to integrate intelligent services into customer-facing applications.
• Identify and resolve architectural and technical challenges affecting application performance, scalability, reliability, and maintainability.
• Provide technical leadership through design discussions, code reviews, mentoring, and hands-on problem solving.
• Help establish longer-term engineering direction while remaining an active individual contributor.

Technical Background

• Significant experience building and scaling sophisticated software products.
• Professional experience developing backend services with Python and modern web frameworks.
• Strong understanding of APIs, distributed application architecture, and full-stack development.
• Experience putting LLM or generative AI capabilities into production software.
• Strong frontend architecture experience, including component systems, state management, performance optimization, and application scalability.
• Comfortable working across application, data, and service layers rather than operating exclusively within one technical discipline.
• Experience partnering with Product and Design to deliver polished customer-facing experiences.
• Demonstrated technical leadership at Staff, Senior Staff, Principal, or equivalent level.
• A history of mentoring engineers and influencing engineering practices beyond your immediate area.

This is an opportunity for an engineer who wants significant architectural influence without leaving hands-on development behind.

You’ll help shape the next generation of an established technology platform, work on meaningful AI-enabled product capabilities, and influence engineering practices as the organization continues to scale.