Senior Backend Engineer (San Francisco)

Onsite San Francisco

180,000 USD + Equity & Benefits

About TestBox

TestBox was founded with a bold mission : to fundamentally transform how software is bought and sold. We're building an innovative platform that empowers buyers with transparent, interactive software experiences, while equipping sellers with powerful tools to deliver exceptional buying and onboarding journeys. Our core technologies - synthetic data, intelligent orchestration, and our unique product graph - help teams achieve faster implementations, clearer insights, and increase trust with their customers.

At TestBox, we're not just improving demos; we're building the next generation infrastructure for software transactions, creating seamless experiences from initial interest to successful onboarding and beyond.

We're a fast-growing startup built by a team that values experimentation, velocity, and customer impact. We're backed by world-class investors and are building a platform that's disrupting the traditional B2B sales motion.

Role Overview

We are hiring a Senior Backend Engineer to help design and build the core of our next-generation platform. This is an opportunity to be a key engineer responsible for creating the central nervous system that will power every product experience at TestBox for years to come.

You will be responsible for building a resilient, scalable, and asynchronous platform from the ground up. The core challenge is to build the backend platform that powers the intelligent automation of complex software environments, tackling problems of scale, resilience, and asynchronous task management. You won't just be implementing specs; you will be a critical voice in the platform's technical direction, making key decisions about technology, scalability, and design patterns.

This role is ideal for a systems thinker who excels at solving complex distributed systems problems and is motivated by the opportunity to build a platform with massive leverage. This is a greenfield opportunity to write the first lines of code for services that will define our business.

What You'll Do

• Design and build the core backend services that enable complex, long-running, and asynchronous operations across multiple systems.
• Create the foundational frameworks and libraries that will be used by the rest of the engineering team to build new product capabilities.
• Design and implement the suite of robust backend services that form the foundation of our new platform, ensuring they are resilient and scalable.
• Partner with leadership to drive key technology and design decisions, and to establish backend engineering best practices.
• Help foster a culture of high-quality code, great design, and a commitment to building for the long term.

Who You Are

• You are a systems thinker , who defaults to designing for resilience, scalability, and observability.
• You are pragmatic and product-aware, able to balance building elegant systems with the iterative needs of a fast-moving startup.
• You are passionate about developer experience and find fulfillment in building tools and frameworks that make other engineers more productive.
• You have a high sense of ownership and are motivated by the accountability that comes with building business-critical systems.
• You communicate technical concepts clearly and are skilled at collaborating with product, design, and other engineers to solve complex problems.

Preferred Experience

• 5+ years of experience in backend software engineering, including building, deploying, and operating complex distributed systems.
• Deep expertise in a modern backend language (e.g., Python, Go, Java, etc.).
• Strong experience with event-driven design, message queues, and asynchronous communication patterns.
• Hands-on experience with modern cloud infrastructure (e.g., AWS, GCP) and containerization technologies.
• Experience designing data models and working with a variety of database technologies to fit different needs.
• A strong understanding of API design principles and best practices.
• Bonus : Direct experience with workflow / orchestration engines.
• Bonus : Experience building developer tools, SDKs, or public-facing APIs.

Why Join TestBox

• Build foundational, greenfield systems from the ground up and make a massive impact from day one.
• Solve challenging and rewarding distributed systems problems.
• Shape the technical foundation that will power the company's growth for the next decade.
• Join a company obsessed with customer experience, speed, and scale.

Benefits

• Generous equity package for meaningful ownership.
• Prioritization of your professional growth, with dedicated career development support.
• Flexible, unlimited PTO with a minimum expectation for recharge.
• Mental Health benefits.
• Fitness allowances.
• Learning allowances.
• Remote and office setup allowances to ensure productive and comfortable working environments.