Senior Backend Engineer - Client integrations

About Cobalt Streamworks : Insurance is a $7T global industry built on professional labor: underwriting, claims, pricing, operations, and distribution. Cobalt Streamworks is building AI that can perform that work. We create professional-grade AI systems for insurers: software that can read, reason, decide, and act inside real workflows and operate over long-time horizons. Cobalt Streamworks begins by augmenting professionals with the tools to succeed at their jobs. That earns us the right to learn from real decisions, capture decision traces, and automate what can be automated successfully over time. Our products are already in production with leading insurers, driving measurable outcomes and expanding across functions. The opportunity is far broader than any single workflow: to build the AI operating system for decision-making across insurance. For people who want to work on AI that matters, in a sector where correctness, trust, and real-world impact count, Cobalt Streamworks is just getting started. Cobalt Streamworks is backed by leading investors such as IA Ventures and Inspired Capital, and our team brings experience from Facebook, Palantir, Google, Amazon, McKinsey, Mastercard, and Uber. Our Values (This is important): Many organizations have a dusty list of corporate values that no one ever follows. Cobalt Streamworks is not one of those companies. Our values are designed to unlock the potential of our employees. Success at Cobalt Streamworks is bred from five core principles: Hustle and Determination - We hire people who take full ownership of their craft and relentlessly pursue excellence with speed and determination. We choose the hard problems and do not give up. This is the foundation of how we work and how we win. Deliver Customer Impact - We're obsessed with customer impact. Every feature, every line of code, every decision is measured against one question: does this help insurers make better decisions? If it doesn't drive speed, accuracy, or profitability for our customers, we don't build it. Meritocracy - We're building something exceptional, and that requires exceptional people and ideas. We have a high bar but we reward excellence with rapid growth. If you're the best at what you do, you'll thrive here. Transparency - We value honest, transparent communication over politics. We challenge ideas, not people. We say what needs to be said, even when it's hard. This is how we solve problems fast and find the truth. Experiment Relentlessly - Many of the problems we face have never been solved before. We tackle them by testing quickly, measuring rigorously, and iterating until we find the path forward. Speed of learning is our advantage. In addition to our NY office, we have remote employees speaking 10+ languages across the globe. But we invest in bringing our people together both for regional meetups and global offsites (2021 - Playa Del Carmen | 2022 - Rome | 2023 - Buenos Aires | 2024 - Lisbon | 2025 - Cartagena). Cobalt Streamworks ’s culture isn’t for everyone, and that’s ok. But for the people who are a fit, they can’t imagine working elsewhere. About the role: Salary range: $165k – $225k USD* We are looking for smart engineers who love to code, seek challenging problems, and appreciate recognition for excellent work. As part of the Client Integrations team, you will work on the external-facing APIs that power our customers’ core workflows. Your day-to-day will involve designing and building API endpoints, improving database and query performance, and integrating with a wide range of third-party services. You’ll translate product requirements into reliable business logic, help diagnose and resolve customer issues, and contribute to making our platform faster, more stable, and easier to use. You'll collaborate with a global team of full-stack, data, ML, and DevOps engineers to build scalable backend solutions as we continue to grow. We're a small team where individual contributions have an outsized impact on both our technology and our business. You'll be right at home if you: Have 5+ years of software engineering experience, ideally with time spent building external-facing APIs or designing integrations with 3rd party systems. Embody hustle and grit, you're excellent at your craft and relentless in pursuing it. Take full ownership of your work and drive projects to completion with minimal oversight. Communicate proactively, surfacing blockers, asking the right questions, keeping stakeholders in the loop. Thrive on experimentation: you're comfortable testing ideas, measuring results, and iterating quickly on problems no one has solved before. Have strong fundamentals in system design, debugging, and problem-solving. Know Python (our main stack), though we're open to strong candidates from other OO backgrounds. Have experience with serverless technologies (Lambda, EC2), asynchronous workflows, and cloud environments. Are comfortable with relational databases, ideally PostgreSQL. Bonus: experience with LLMs/generative AI, distributed systems. What you’ll get: Competitive salary (based o