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Rainbow is solving the problem of estimating the risk underlying the most difficult categories of business insurance.

We’re building insurance from first principles—owning the full stack from underwriting to claims—with real production scale and real-world impact.

Founded in early 2022, we’ve grown quickly: over 3x revenue growth in the past year, expanded product offerings, and a successful Series A backed by leading investors. In 4 years, we’ve become one of the largest insurers of restaurants in the U.S., and we’re just getting started as we expand into new verticals.

Our platform combines proprietary insurance products with software that automates quoting, underwriting, and claims. And most of all, it does that all while leading the insurance industry when it comes accurately determining the risk.

Engineering Culture

We operate as a small, high-ownership engineering team—engineers work directly with product and insurance stakeholders, and ship to production frequently. We value in-person collaboration because many of our hardest problems are ambiguous and benefit from tight feedback loops.

What Makes This Role Interesting

• Modeling real-world insurance workflows: Policies, endorsements, claims, and audits with high correctness requirements.
• Correctness + performance: Design systems where correctness matters as much as latency—mistakes have real financial consequences.
• Scale with a small team: Build infrastructure that can scale rapidly while staying simple enough for a lean team to own.

What You’ll Do

As a Senior Backend Engineer, you will:

• Own Core Systems: Design and build backend services powering quoting, underwriting, claims, and policy management.
• Design for Agility & Long-Term Code Health: Build systems that are easy to change, well-factored, and maintainable over time—without sacrificing reliability and observability.
• Partner Across Teams: Work closely with product and insurance teams to deliver end-to-end solutions.
• Raise the Bar: Write high-quality, well-tested code and mentor teammates on best practices.

About You

• Backend-Focused Engineer: You’ve built and owned backend systems in production (Go experience is a plus, not required).
• Strong System Design Skills: You design systems that are scalable, resilient, and easy to reason about.
• Ownership Mindset: You’re comfortable making tradeoffs across speed, correctness, and complexity.
• Collaborative: You communicate clearly and work effectively with cross-functional partners.
• Quality-Oriented: You prioritize maintainability, testing, and thoughtful design.
• Experienced: 5+ years of backend development experience in production environments.

Example Problems You Might Work On

• Designing a policy lifecycle system that supports midterm endorsements and audits.
• Building a real-time underwriting engine that identifies and flags risks.
• Building an AI workflow to agentically research a business submitted to us for a quote.

Team & Tech

• Team Size: 40+ total employees, including 9+ engineers.
• Backend: Golang (knowledge of Go is not required)
• Database: Postgres
• Cloud Provider: AWS

Location & Schedule

• Office Location: Financial District, San Francisco.
• Work Schedule: In-office twice per week (Mondays and Thursdays)