Founding Engineer

Job DescriptionABOUT HYPERLOOP\n\nWe're building the Finance OS for the office of the CFO. Our agents run accounts receivable end to end — chasing invoices, answering payer questions, resolving disputes, applying cash. Autonomously, in production today, against real ledgers.\n\nEnterprise, mid-market and self-serve, on one platform. Live with paying customers on signed annual contracts.\n\nTHE ROLE\n\nFounding Engineer. Full-stack, leaning hard into ML. You'd own the product surface and the agent layer underneath it, with real authority over the architecture and where it goes next.\n\nWHY WE NEED YOU\n\nYou've probably been the person on your team who actually understands how the system behaves in production — not just how it was designed. You've shipped ML into something real, watched it degrade in ways the offline metrics didn't predict, and built the tooling to catch that next time.\n\nYou're tired of having the interesting architectural decisions made two levels above you. You'd rather own a hard problem end to end, with the authority to decide how it gets solved, than optimise a slice of someone else's.\n\nTHE HARD PROBLEMS\n\nAgents that run for months, not minutes. Durable state, replanning, idempotency, recovery. No framework does this.\n\nCredit assignment on sparse, delayed, confounded outcomes — and the offline eval to ship against it, because you can't A/B against real money.\n\nAutonomy with hard guarantees. Actions hit a real ledger. "Probably right" isn't available.\n\nPlus the usual, done properly: multi-tenant isolation, high-throughput reconciliation, exactly-once scheduling, flaky third-party APIs, inference cost and latency, observability that still answers questions six weeks later.\n\nALSO YOURS\n\nModel strategy — what runs where, and the quality/cost/latency tradeoff per decision type.\n\nDeep integration with systems of record — not just reading, but acting in them safely and reversibly, to a standard an auditor accepts.\n\nThe product itself — onboarding, dashboards, the control plane that makes a team willing to switch autonomy on.\n\nPlus the founding-engineer tax: CI, observability, on-call, the security questionnaire that unblocks a deal.\n\nWHAT WE'RE LOOKING FOR\n\nStrong Java and Python, plus real ML engineering experience. Backend discipline alongside the ability to train, evaluate and ship models that survive production.\n\nNo fixed years requirement — but we'll want referenceable experience, not a reading list.\n\nYou've shipped production systems and owned them afterwards.\n\nML and LLM work beyond prompting: fine-tuning, evals, retrieval, agent orchestration, or the cost/latency tradeoffs that decide what's viable.\n\nComfortable owning product surface as well as models, and comfortable being the one who decides.\n\nHelpful, not required: fintech, accounting or ERP domain experience; a prior founding-engineer role; financial-grade correctness and audit requirements; anything public that shows you ship.\n\nTHE STACK\n\nJava, Python and TypeScript. Anthropic API alongside open-weight models. DigitalOcean, GitHub, Google Workspace. Integrations into NetSuite, Business Central, Sage Intacct and QuickBooks. Slack is a first-class surface, not a notification channel.\n\nYou'd have real influence over what this becomes — several of these decisions are still open.\n\nHIRING PROCESS\n\nTwo steps. No take-home marathon, no LeetCode.\n\n\n Intro call with the founder. What you've built, what you want to own, how the comp structure lands for you.\n Solve a real problem — one session, a problem from our actual domain. Use whatever you like, including Claude Code, Cursor or any other agent. We care how you think and how you use the tools.\n\nCOMPENSATION\n\nFounder-level equity, 0.5–5%, vesting on a standard schedule from your start date.\n\nNo cash salary until our seed round closes, at which point the role converts to salary.\n\nHOW TO APPLY\n\nApply here, or email View email address on click.appcast.io with something you built that you're proud of and what was hard about it, a repo or demo, and what you'd want to own first.\n\nNo cover letter. We reply within 72 hours either way.\n\nMore at hyperloopai.io