Senior Backend Engineer

Important Note: This role requires in-office presence at our San Francisco office at least 4 days a week.

About us

TestBox was founded with a bold mission: to fundamentally transform how software is bought and sold.

Today, most enterprise software is still sold through static demos and slide decks. TestBox replaces that with real, interactive product experiences powered by synthetic data, intelligent orchestration, and our proprietary product graph. Instead of imagining how software might work, buyers can actually test it in realistic environments before they buy.

We’ve raised $27M in funding to date, with Airtree leading our Series A and participation from Skip Capital, Glitch Capital, K8, and SignalFire. This funding allows us to accelerate our vision of building the infrastructure that powers modern software transactions

To share more about the vision for TestBox and the product direction ahead, our CEO recently announced the Series A and several new product developments.

Watch the announcement here.

At TestBox, we’re not just improving demos. We’re creating the next generation platform for how software is evaluated, purchased, and implemented, enabling teams to move from first interaction to successful onboarding faster and with greater trust.

We’re a fast-growing startup built by a team that values experimentation, velocity, and customer impact, and we’re just getting started.

Who we are looking for

We’re hiring a Senior Backend Engineer to design and build the core of our next-generation platform; the system that powers every product experience at TestBox. You’ll work on a greenfield project tackling challenges in scale, resilience, and automation, building a robust and asynchronous backend that drives intelligent software environments.

This role goes beyond implementation. You’ll help shape the technical direction, making key decisions around architecture, scalability, and performance while collaborating closely with product and design to turn ideas into reliable, high-impact systems.

We’re looking for a systems thinker who’s pragmatic, values developer experience, and thrives in distributed environments. You’ll take ownership, communicate clearly, and enjoy building tools that make other engineers more productive.

You have

• 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, Ruby, 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.

You will

• 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.

What success looks like

In the first 90 days, you will ramp up quickly, get deeply familiar with our architecture, and start contributing to core platform development. You’ll experiment confidently with AI tooling, work with a “minimum marketable product” mindset, and deliver new features or improvements on a weekly cadence. By the end of this period, you’ll be fully embedded in the team and trusted to own key backend services.

By 12 months, you will have built/significantly shaped the core backend systems that power TestBox’s next-generation platform. Your work will be directly supporting live customer experiences and driving measurable business impact. You’ll be seen as a go-to engineer for technical decision-making, someone who raises the bar for code quality, and a teammate others genuinely enjoy collaborating with. The platform will be faster, more scalable, and customers will be actively buying and loving the product you helped build.

The 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.

We believe that diversity is critical to our success. We will not discriminate on the basis of race, religion, national origin, gender identity or expression, sexual orientation, age, or marital, veteran, or disability status.