Sr. Backend Engineer

**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. We help merchants and consumers connect, transact, and complete payments, whether they are online or in person. 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. We enable consumers to exchange funds more safely with merchants using a variety of funding sources, which may include a bank account, a PayPal or Venmo account balance, PayPal and Venmo branded credit products, a credit card, a debit card, certain cryptocurrencies, or other stored value products such as gift cards, and eligible credit card rewards. Our PayPal, Venmo, and Xoom products also make it safer and simpler for friends and family to transfer funds to each other. We offer merchants an end-to-end payments solution that provides authorization and settlement capabilities, as well as instant access to funds and payouts. We also help merchants connect with their customers, process exchanges and returns, and manage risk. We enable consumers to engage in cross-border shopping and merchants to extend their global reach while reducing the complexity and friction involved in enabling cross-border trade.

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 - and they push us to ensure we take care of ourselves, each other, and our communities.

**Job Description**:
Key Responsibilities
- Backend Architecture: Design, build, and optimize scalable and resilient backend systems using modern cloud-native technologies.
- AI Integration: Work closely with ML engineers to integrate AI models into backend services, enabling smart, adaptive experiences.
- API & Service Design: Develop robust RESTful and GraphQL APIs and microservices to support web and mobile clients.
- Performance & Reliability: Ensure systems are highly available, secure, and performant through monitoring, load testing, and optimization.
- Data Engineering & ML Ops: Build efficient data pipelines, support model training/inference workflows, and deploy ML models in production.
- Security & Compliance: Implement best practices around authentication, data protection, and secure architecture design.
- Cross-Functional Collaboration: Partner with product, frontend, DevOps, and data teams to align engineering efforts with business strategy.
- Mentorship & Leadership: Mentor junior engineers, lead code reviews, and champion engineering best practices.
- Tech Strategy & Innovation: Stay up-to-date with industry trends in backend infrastructure, AI/ML, and cloud services; advocate for technology adoption and innovation.

Required Skills & Experience
- 10+ years of backend engineering experience in large-scale systems
- Proficiency in Node.js, Python, Java, or Go, with strong system design and debugging skills
- Experience deploying and scaling systems on AWS, GCP, or Azure
- Hands-on experience with AI/ML model integration, including inference pipelines and model lifecycle management
- Deep understanding of API design, microservices, and event-driven architectures
- Strong knowledge of SQL and NoSQL databases, message queues, and distributed data systems
- Familiarity with CI/CD, containerization (Docker), and orchestration tools (Kubernetes)
- Experience with monitoring tools like Datadog, Prometheus, or OpenTelemetry
- Knowledge of security best practices, data privacy, and compliance (e.g., GDPR)
- Excellent communication and collaboration skills in agile teams

**Preferred Qualifications**
- Experience with **ML Ops** tools (e.g., MLflow, Kubeflow, Vertex AI)
- Background in **deep learning frameworks** (e.g., TensorFlow, PyTorch)
- Exposure to **vector databases**, **LLM integration**, or **retrieval-augmented generation (RAG) pipelines**:

- Experience building **recommendation systems**, **chatbots**, or **predictive services**:

- Knowledge of **backend observability**, **circuit breaking**, and **self-healing systems**:

- Understanding of **data governance**, **feature stores**, and **stream processing**

For the majority of employees, PayPal's balanced hybrid work model offers 3 days in the office for effect