Senior Software Engineer

Founding Senior Software Engineer$180,000 - $280,000 + Very High Equity + 401(k) + Benefits + Flexible PTOSan Francisco, CA - On-site (5 days/week)Are you a Senior Software Engineer with full stack experience, looking to join a one of the strongest YC start-ups of recent batches, that is transforming one of the largest and most under-optimised multi trillion dollar industries in the world?This is an exciting opportunity to join a fast-growing YC-backed AI startup that has raised one of the largest seeds in its space, is already working with some of the biggest enterprise names in its industry, and has hit Series A metrics within months of founding. The team is building an agentic AI platform that replaces deeply entrenched manual workflow— deploying AI agents that handle complex, compliance-heavy tasks that have been done by hand for decades. The CEO and CTO are both multiple-time YC founders with exits under their belt, and their seed round was led personally by one of YC’s most respected partners – these are seriously high conviction founders.As one of the first engineers, you'll be helping to build core product from scratch - AI agents, evaluation systems, human-agent interaction patterns, and secure backends for a regulated enterprise customer base. As mentioned, the founders have previously built and exited a VC-backed startup in this space and scaled engineering teams through hyper-growth, so you'll be working with people who know exactly what they're doing and why.This is a hands-on, high-impact role for engineers who bring senior technical depth, thrive in ambiguity, and want to operate at the intersection of cutting-edge AI and a market that is genuinely ready to be disrupted, in a company where the foundations are as solid as they come.The RoleBuild new AI agents and features from scratch across the full stackBuild and maintain evaluation frameworks to ensure accuracy and correctness across highly specialised, compliance-heavy insurance workflowsIterate on design and human-agent interaction patternsEmbed regulatory and legal compliance directly into AI tasks and workflowsBuild backends that support fast-scaling agentic workloadsSecure systems for a highly discerning and regulated enterprise customer baseWork directly with customers to understand problems and validate solutionsThe Person3+ years of professional software engineering experienceProficiency in TypeScript, React, Next.js, Node.js, and AWSHands-on experience building with AI agents and agentic frameworksStrong communication skills (you can talk to enterprise customers as confidently as you can talk to engineers)Comfortable working independently with high ownership in a fast-moving, in-person environmentBased in or willing to relocate to San Francisco