Senior Backend Engineer

💰 $200,000 USD + Equity & Benefits

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.

We’re hiring a Senior Backend Engineer to help build and evolve the platform that powers TestBox.

While our core product is already live and delivering value to customers, we’re now building Monarch, our next-generation agentic platform that will orchestrate and automate complex software environments.

This is not a maintenance role. You’ll be working on new systems, new architecture, and new platform capabilities, helping us transition from early product to a fully scalable, intelligent platform.

• Design and build backend systems that power the product and agentic workflows
• Evolve and re-architect core services for scalability and performance
• Build frameworks and infrastructure used across the platform
• Work on distributed, asynchronous systems operating at scale
• Partner with leadership on long-term platform and architectural decisions

• 5+ years of experience in backend software engineering, including building, deploying, and operating complex distributed systems.
• Expertise with modern, backend languages incl Go, Python, Rust, Node (TypeScript).
• Strong experience with event-driven design, message queues, and asynchronous communication patterns.
• Hands-on experience with modern cloud infrastructure (e.g., AWS, GCP)
• 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

• 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.

• Unlimited access to AI tools
• Unlimited token budget
• 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.