Senior Full-Stack Engineer (Frontend Focus)

Position Overview

TestBox is on a bold mission to transform how software is bought and sold. As a fast-growing startup backed by world-class investors, we empower buyers with transparent, interactive software experiences and equip sellers with powerful tools for exceptional onboarding. We are seeking a Senior Full-Stack Engineer with a strong Frontend focus to build sophisticated, interactive tools for our next-generation platform. This is an on-site role in San Francisco. Compensation: $200,000 USD + Equity & Benefits.

Key Responsibilities

• Build rich, interactive user interfaces for the platform's core authoring tools, including visual workflow creation and data management/visualization.
• Design, build, and modify API endpoints in our Django backend to support new user interfaces and ensure seamless data flow.
• Collaborate closely with product design to iterate on prototypes and deliver polished, high-quality user experiences.
• Establish the foundation for our frontend architecture, including a component library, state management strategy, and testing best practices.
• Work with backend engineers on the Platform team to define and integrate with core services.

Required Qualifications

• A product-focused mindset with deep care for user experience and attention to the "why" behind feature-building.
• Proven ability to turn complex problems into simple, elegant user interfaces.
• Strong eye for design with high standards for UI polish and interactive details.
• A collaborative spirit with the skills to bridge frontend and backend development.
• A high sense of ownership and accountability when building features end-to-end.

Preferred Qualifications

• 5+ years of experience in software engineering with a strong background in building complex web applications.
• Deep expertise in modern frontend frameworks (e.g., React, Vue, Svelte, etc.) and their ecosystems.
• Proficiency in backend development, preferably with Python and Django, and experience designing, building, and consuming REST APIs.
• Bonus: Experience with data visualization libraries (e.g., D3.js) or developing interactive, canvas-based interfaces.
• Bonus: Background in creating developer tools or B2B SaaS products for technical users.

Benefits & Perks

• Generous equity package for meaningful ownership.
• Dedicated career development support to prioritize your professional growth.
• Flexible, unlimited PTO with a minimum expectation for recharge.
• Comprehensive Mental Health benefits.
• Fitness and learning allowances.
• Remote and office setup allowances to ensure a productive and comfortable work environment.