Senior Backend Software Engineer

— New York, NY Hybrid Full-time $220K–$270K + equity About The Company Our client is a seed-stage, venture-backed AI startup bringing modern software to a large, traditionally underserved industry — building a fully managed platform that ingests, organizes, and analyzes complex documents and data so its customers can make faster, better-informed decisions. They run a lean, AI-native engineering team where individual engineers carry real ownership over both product and architecture. Founded 2020 :20 people Industry: AI / Enterprise Software. The Role We're representing our client in a search for a senior backend engineer to join as a hands-on IC in an early-stage environment — shipping production services, driving key architectural decisions, and mentoring junior engineers, with a clear runway to a lead role in the near term. What You'll Be Doing Design, build, and operate production-grade backend services and data pipelines on a Python + AWS serverless stackMake architectural and system-design decisions, using modern AI coding tools to move quicklyOwn features end-to-end across a primarily backend codebase, with occasional front-end work in ReactWork directly with customers to turn ambiguous requirements into shipped softwareMentor junior engineers through code review, design discussions, and pairing Tech stack: Python, AWS (Lambda, Step Functions, serverless), REST APIs, microservices, event-driven architecture, React Requirements 5+ years in backend software engineeringExperience as a founding engineer or early hire at an early-stage B2B SaaS startup, with genuine end-to-end ownershipA track record of owning production backend systems, not just contributing to themAdvanced, production-level Python skillsStrong hands-on AWS experience, particularly serverless (Lambda, Step Functions)A product mindset and comfort speaking directly with customers to clarify what needs buildingBased in or near New York City and able to work on-site three days a week (Midtown)A BS in Computer Science or a related STEM field, or an equivalently strong startup engineering track record in its place Nice to Haves Prior tech-lead or mentorship experience guiding junior engineersFamiliarity with AI coding tools and agentic development workflows Why Join Build the core platform for a large industry that modern software has barely reachedSmall, well-backed, AI-native team where engineers own product and architecture outrightSenior IC role with a clear near-term path to a lead positionCompetitive base plus meaningful early-stage equity Details Location: New York, NYWork policy: Hybrid — 3 days/week in-office (Midtown)Compensation: $220K–$270K + equityVisa sponsorship: Not available for this roleEmployment type: Full-time