About Antithesis

We provide a platform that helps engineering teams identify and resolve bugs that traditional testing approaches miss. Antithesis runs your entire system in a deterministic simulation, breaks it in every way imaginable, and hands you a root cause and a perfect reproduction — no flaky tests, no false positives, no "works on my machine". This allows engineering teams to debug faster and ship with greater confidence.

The rise of AI-generated code has made what we do more important than ever. Agents can write code faster than any human — but faster code isn't better code if it's buggy, stuck in review, or issues are slipping through the cracks undetected. The verification bottleneck is real, and it's growing. This is exactly the problem Antithesis exists to solve. We've been quietly reinventing how the world thinks about software reliability, and we're just getting started.

We're well-funded, deeply technical, and building a platform that tackles one of the most complex yet important problems in modern software engineering. If that sounds like fun to you, keep reading.

About the Role

The FP&A Manager will be the key builder of Antithesis's next phase of financial planning infrastructure. This person will create a new operating model for a business that is growing quickly, changing constantly, and getting more complex across headcount, go-to-market, product investment, cloud spend, and international expansion.

This is a hands-on builder role for someone who wants to make a huge difference early. You will launch a true budgeting program, improve forecasting and scenario planning, help leaders make faster and better decisions, and identify optimization opportunities across the business. You will start as a high-leverage individual contributor, but this role is ideal for someone with manager energy who is hungry to grow, step into ambiguity, and help shape how Finance supports the company long term.

You should expect to be both strategic and practical: building models, driving planning processes, partnering with leaders, cleaning up messy inputs, and jumping in wherever the business needs help most.

What You’ll Do

• Build and own Antithesis's core operating and forecasting model across revenue, headcount, compensation, cloud and infrastructure spend, vendor spend, and other major operating drivers.

• Redesign planning for a rapidly changing business, creating a model that can flex with shifting priorities, new investments, changing hiring plans, and evolving go-to-market motion.

• Launch and run a full company budgeting program, including annual planning, in-year reforecasts, variance analysis, and department-level partnership.

• Partner with department leaders to translate plans into budgets, challenge assumptions, surface tradeoffs, and improve accountability around spend and hiring decisions.

• Develop scenario analyses that help leadership evaluate growth paths, investments, cost optimization opportunities, and strategic decisions with speed and clarity.

• Support international expansion planning by modeling new entities, country launches, hiring options, payroll implications, and operating costs.

• Improve management reporting and financial visibility through better KPI tracking, clearer reporting packages, and more decision-useful analysis.

• Work closely with Accounting to ensure forecasts tie cleanly to actuals and that planning assumptions reflect operational reality.

• Evaluate and improve the tools, processes, and data flows that support budgeting, forecasting, and business performance analysis.

• Support executive, board, and investor-ready materials with clear analysis, thoughtful commentary, and strong financial storytelling.

• Step into ad hoc projects that create leverage for the broader Finance function and help the company operate more effectively as it scales.

What We’re Looking For

You do not need to hit every bullet here, but candidates tend to be strongest when they bring most of the following.

Background and Experience

• 6+ years of experience in FP&A, strategic finance, finance business partnering, or related roles, ideally in a high-growth SaaS, software, or startup environment.

• Strong track record building or rebuilding operating models in a business that is scaling quickly or changing meaningfully.

• Experience standing up or materially improving budgeting and forecasting processes, not just maintaining an existing model.

• Experience partnering with senior leaders on headcount planning, spend management, investment decisions, and business performance analysis.

• Exposure to international expansion, multi-entity planning, or global operating complexity is strongly preferred.

• Experience supporting board, leadership, or investor-facing analysis is a plus.

Technical Skills

• Excellent modeling skills in Excel; able to build clear, flexible, decision-useful models from imperfect inputs.

• Strong financial and business judgment across headcount, compensation, operating expenses, margin drivers, growth investment decisions, and the accounting implications behind them.

• Clear understanding of GAAP and accrual-based financial modeling, with the ability to build planning models that align to how the business should be viewed on an accrual basis, not just cash activity.

• Ability to build and maintain cash models and cash forecasts alongside accrual-based operating models, with a practical understanding of working capital, payment timing, and cash flow implications of business decisions.

• Comfort turning messy or incomplete data into structured analysis and actionable recommendations.

• Experience with financial systems, planning tools, ERP environments, or BI/reporting platforms is a plus, especially if you have helped improve the tooling stack.

• Ability to connect financial outputs to operational drivers and explain the why behind the numbers.