Senior Product Manager in London

About Antithesis

Antithesis is building a fundamentally new approach to software testing. Our platform uses advanced fuzzing and property-based testing techniques to find deep bugs in customer software and exercise systems in ways that traditional testing cannot. We are in the early stages of productizing a powerful underlying technology. That means much of our product surface, operating model, and customer workflows are still being defined. This is a high-ambiguity, 0 1 environment where product judgment matters.

About the Role

We are hiring Product Managers to own critical parts of the Antithesis product. This is not a purely executional role inside an established system. You will operate in a fast-moving, technical environment where many decisions are first‐of‐their‐kind. You will help define product areas, shape workflows, influence prioritization, determine how we measure success, and partner closely with engineering and design to build durable foundations. You will operate in a technical, engineering‐heavy environment where problems are complex and tradeoffs are real. You'll work closely with engineers to define what we build, why we build it, and how we measure success. This is not a role for someone who wants to run process or optimize a mature product. It's a role for someone who wants to build.

Areas of Focus

We are looking for a London‐based product manager to own the Property‐Based Testing (PBT) and Specification product area. This area includes, but is not limited to:

• How customers expose their software for Antithesis to exercise during a test.
• How customers tell us what behaviour is expected or not expected of their software.
• How customers tell us which kinds of issues they do or do not care about.
• How customers provide us with guidance on what areas of their code are most interesting to explore.
• The Antithesis SDK.

You will work closely with the Antithesis PBT technical team, based out of the London office, which includes world experts on property‐based testing.

What You'll Do

• Conduct discovery sessions with customers and understand their needs.
• Define and prioritize product initiatives within your area.
• Work with engineering to scope and ship high‐impact features.
• Make tradeoffs in ambiguous and technically complex situations.
• Define metrics and evaluate outcomes.
• Collaborate with GTM and customers to refine requirements.
• Write clear product briefs and problem statements.

What We're Looking For

Strong Signals:

• Startup experience.
• Experience defining developer‐facing APIs or abstractions.
• Comfort operating under ambiguity.
• Evidence of thoughtful prioritization and decision‐making.
• Strong written communication.

Nice to Have:

• Experience with property‐based testing, fuzzing, and/or formal verification.
• Experience with distributed systems.
• Software testing background.

Not a Fit If

• You focus primarily on implementing PM frameworks or process.
• Your experience centers on optimizing mature systems without building new ones.
• You prefer highly structured environments with predefined playbooks.

Equal Opportunity Statement

We are an equal opportunity employer and value a diverse, inclusive workplace. We do not discriminate on the basis of race, religion, colour, national origin, gender, sexual orientation, gender identity or expression, age, marital or veteran status, pregnancy, disability, or any other protected characteristic. We are committed to providing reasonable accommodations throughout the application and employment process.