Payroll & Accounts Payable Specialist

About Antithesis We build a platform that finds the bugs other testing approaches never see. Antithesis runs your entire system inside a deterministic simulation, breaks it in every way we can think of, and hands you a root cause with a perfect reproduction — no flaky tests, no false positives, no "works on my machine." Engineering teams debug faster and ship with far more confidence. AI-generated code has made this work more urgent than ever. Agents write code faster than any human can, but faster code isn’t better code if it’s buggy, stuck in review, or quietly failing in production. The verification bottleneck is real, and it’s growing. That is precisely the problem Antithesis exists to solve. We’ve spent years quietly rethinking how the world approaches software reliability, and we’re just getting started. We’re well-funded, deeply technical, and headquartered in Northern Virginia with satellite offices in London and San Francisco. Our team is in the office daily, which is how we take on hard problems together. If that sounds like fun to you, keep reading. About the Role Antithesis is looking for someone to own payroll and accounts payable as we scale. You'll keep employees paid accurately and on time, vendors paid to terms, and our expense processes clean while building the infrastructure that will support a much larger company. This role sits at the operational center of finance. We run lean, so the work is hands-on. You should be comfortable managing competing deadlines, handling sensitive data, and improving process without being asked. We're in the office daily in Vienna, VA. What you'll do - Process payroll for a multi-state workforce, accurately and on time - Manage accounts payable end-to-end: invoice intake, approval routing, payment execution, and reconciliation - Administer the employee expense reimbursement process and corporate card program - Support benefits administration in coordination with HR - Maintain payroll records and prepare reports for audit, tax, and internal purposes - Stay current on state and local payroll tax compliance as we add employees in new jurisdictions - Identify and drive improvements to payroll and AP systems and workflows What we're looking for - 3+ years of payroll and accounts payable experience, ideally at a tech or growth-stage company - Experience with payroll platforms (Rippling, Gusto, ADP, or similar) and accounting systems (NetSuite preferred) - Working knowledge of multi-state payroll tax requirements - High bar for accuracy and ability to handle confidential information with discretion - Organized and deadline-driven - Process-oriented: you look for ways to make things better, not just keep them running