Tax & Treasury Manager

Why this role exists

As PortSwigger continues its global growth, our financial landscape is becoming more complex and exciting. Our tax and treasury functions are no longer just about compliance; they are a strategic engine for commercial growth. We're not looking for a typical compliance officer; we're looking for a leader to unlock our full financial potential.

This is a unique opportunity to build and shape our tax and treasury functions from the ground up. You will have the autonomy to design and implement scalable policies that not only manage risk but also create tangible financial value. If you are driven to see your expertise directly impact business outcomes and want to grow into a trusted strategic advisor, this role is for you.

What you’ll be doing

You'll take full ownership of our tax and treasury operations, transforming them into a strategic advantage for the business.

Strategic Enablement & Planning:

• Move beyond compliance to identify and execute commercial opportunities through smart tax planning, focusing on initiatives like UK R&D credits and the Patent Box regime.
• Advise on the tax implications of international expansion, new product launches, and pricing structures, ensuring we are always one step ahead.
• Develop and maintain our transfer pricing documentation, shaping our IP and legal entity structuring to support efficient growth.
• Monitor global economic trends and legislative changes, proactively assessing their impact and developing strategies to protect and enhance the business.

Treasury & Risk Management:

• Own and nurture relationships with our banking partners to ensure optimal service and support.
• Develop and implement scalable treasury policies that manage foreign exchange risk and optimize cash flow.
• Collaborate with the FP&A team to identify investment opportunities and generate returns on our cash reserves.

Compliance & Operations:

• Manage all international and local tax obligations, including corporate tax, VAT/sales tax, and employment taxes, with a key focus on our significant UK and US operations.
• Oversee all tax filings, working with external partners where necessary, and own our US sales tax compliance using Vertex.
• Act as the go-to subject matter expert for all tax-related queries, translating complex concepts into clear, accessible language for the wider business.
• Lead any tax authority audits and maintain robust internal controls to ensure we are always audit-ready.

About you

We're looking for a unique blend of technical expertise, strategic thinking, and personal drive.

• You have a strong background in accounting or tax, holding an ACA or CTA qualification, and have 5-8 years of experience, ideally starting your career in a Big 4 or Top 10 firm.
• You have since moved 'in-house' to a scaling SaaS or tech company and have deep domain knowledge in international tax, particularly for UK and US jurisdictions.
• You're genuinely passionate about your specialism—described by friends as dependable, calm, and endlessly curious. You love diving deep into complex, multi-jurisdictional problems.
• You are a clear, pragmatic communicator who can connect financial details to broader business outcomes for non-finance stakeholders.
• You thrive on autonomy and are motivated by seeing the tangible financial impact of your work, getting frustrated by bureaucracy and purely administrative tasks.

Why join PortSwigger?

We’re a team of curious, driven people working together to secure the web. Our culture is our superpower—collaborative, human, and focused on meaningful work. We provide an environment where you can do your best work, grow your expertise, and see the real-world impact of your contributions.

Read more about our culture and values on our Careers page.