Senior Software Engineer, Ads Tech in London

The Company PayPal has been revolutionizing commerce globally for more than 25 years. Creating innovative experiences that make moving money, selling, and shopping simple, personalized, and secure, PayPal empowers consumers and businesses in approximately 200 markets to join and thrive in the global economy. We operate a global, two-sided network at scale that connects hundreds of millions of merchants and consumers.

PayPal is more than a connection to third-party payment networks. We provide proprietary payment solutions accepted by merchants that enable the completion of payments on our platform on behalf of our customers. We offer our customers the flexibility to use their accounts to purchase and receive payments for goods and services, as well as the ability to transfer and withdraw funds.

Our beliefs are the foundation for how we conduct business every day. We live each day guided by our core values of Inclusion, Innovation, Collaboration, and Wellness. Together, our values ensure that we work together as one global team with our customers at the center of everything we do.

Job Summary: PayPal’s Ads Tech team is building our next-generation advertising platform—a greenfield initiative combining advanced AI, large-scale systems engineering and PayPal’s unique merchant and transaction insights. As a Senior Software Engineer, you’ll help design and develop key parts of the platform, shape the technical roadmap and build reliable systems capable of operating at significant scale.

Essential Responsibilities:

• Delivers complete solutions spanning all phases of the Software Development Lifecycle (SDLC) (design, implementation, testing, delivery and operations), based on definitions from more senior roles.
• Advises immediate management on project-level issues.
• Guides junior engineers.
• Operates with little day-to-day supervision, making technical decisions based on knowledge of internal conventions and industry best practices.
• Applies knowledge of technical best practices in making decisions.

Minimum Qualifications:

• 3+ years relevant experience and a Bachelor’s degree OR Any equivalent combination of education and experience.

Additional Responsibilities & Preferred Qualifications:

• Design and develop core components of PayPal’s advertising platform.
• Contribute to the technical roadmap and help turn complex requirements into scalable software designs.
• Build cloud-native backend systems with a strong focus on performance, resilience and maintainability.
• Champion software craftsmanship, strong coding standards and tools that improve code quality.
• Drive innovation and incremental improvements by taking initiative and challenging existing approaches.
• Collaborate with Product, Engineering and other cross-functional teams to navigate ambiguity and deliver meaningful business outcomes.
• Help create fault-tolerant systems designed for high availability and disaster recovery.
• Share knowledge, support fellow engineers and contribute to an inclusive, collaborative engineering culture.

What We’re Looking For:

• A highly experienced engineer with strong analytical and systems-design skills.
• Deep appreciation for functional programming and its application to production systems.
• A pragmatic problem-solver who can balance technical quality, scalability and business needs.
• Someone comfortable working within a greenfield environment where not every problem has an established playbook.
• A collaborative engineer who values collective success, constructive feedback and continuous learning.
• A strong advocate for clean, reliable and maintainable code.

What You’ll Bring:

• 10+ years of software development experience, with a strong emphasis on functional programming.
• Proficiency in at least one functional programming language—ideally Scala and its Typelevel ecosystem.
• 5+ years of experience designing and architecting scalable backend systems, including cloud-native solutions, microservices or serverless architectures.
• Experience with functional effect systems such as Cats Effect or ZIO.
• Expertise in building fault-tolerant, highly available systems and planning for disaster recovery.
• Hands-on experience with at least one major cloud platform, such as AWS, Google Cloud or Microsoft Azure.
• Experience developing large-scale, high-performance systems.
• Experience working within Agile or Scrum software-development environments.

Nice to Have:

• Python development experience, particularly within a machine-learning context.
• Knowledge of advertising technology, payment processing or the regulatory considerations surrounding these industries.

We Believe in You Interested? Don’t hesitate to apply or reach out and let’s talk — We’d love to learn more about you!

PayPal does not charge candidates any fees for courses, applications, resume reviews, interviews, background checks, or onboarding. When making an application directly, we will never ask you to share passwords, one-time passcodes (OTP), or verification codes. Any such request is a red flag and likely part of a scam.

For the majority of employees, PayPal's balanced hybrid work model offers 3 days in the office for effective in-person collaboration and 2 days at your choice of either the PayPal office or your home workspace, ensuring that you equally have the benefits and conveniences of both locations.

Our Benefits: At PayPal, we’re committed to building an equitable and inclusive global economy. And we can’t do this without our most important asset-you. That’s why we offer comprehensive, choice-based programs, to support all aspects of personal wellbeing—physical, emotional, and financial—delivering meaningful value where it matters most.

Who We Are: Commitment to Diversity and Inclusion PayPal provides equal employment opportunity (EEO) to all persons regardless of age, color, national origin, citizenship status, physical or mental disability, race, religion, creed, gender, sex, pregnancy, sexual orientation, gender identity and/or expression, genetic information, marital status, status with regard to public assistance, veteran status, or any other characteristic protected by federal, state, or local law.