Staff Machine Learning 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 Summary:

This job will lead the design, development, and implementation of advanced machine learning models and algorithms to solve complex problems. You will work closely with data scientists, software engineers, and product teams to enhance services through innovative AI/ML solutions. Your role will involve building scalable ML pipelines, ensuring data quality, and deploying models into production environments to drive business insights and improve customer experiences.

Job Description:

Essential Responsibilities:

• Lead the development and optimization of advanced machine learning models.
• Oversee the preprocessing and analysis of large datasets.
• Deploy and maintain ML solutions in production environments.
• Collaborate with cross-functional teams to integrate ML models into products and services.
• Monitor and evaluate the performance of deployed models, making necessary adjustments.

Minimum Qualifications:

• 5+ years relevant experience and a Bachelor’s degree OR Any equivalent combination of education and experience.
• Extensive experience with ML frameworks like TensorFlow, PyTorch, or scikit-learn.
• Expertise in cloud platforms (AWS, Azure, GCP) and tools for data processing and model deployment.

Domain

1.        Knowledge of Credit, Payments or any other financial product or services domain

Generative AI

• Deep expertise in foundation model development using transformer architectures, including pretraining strategies, model scaling, and optimization techniques
• Proficient in LLM fine-tuning methodologies including supervised fine-tuning (SFT), RLHF, REFT, DPO, and parameter-efficient methods such as LoRA and QLoRA
• Strong experience designing and implementing LLM guardrails, including safety filters, output validation, toxicity detection, and policy enforcement frameworks

Recommendation Systems

• Deep experience in building large scale recommender systems for product/content recommendation
• Solid understanding of foundation models for recommendation systems, including architectures such as Transformers4Rec
• Experience with RL based recommenders such as Multi-armed bandits is an added plus

Agentic AI

• Hands-on experience building production-grade Agentic AI applications, including multi-agent orchestration, tool use, memory systems, and autonomous reasoning pipelines
• Ability to pick up new agentic AI frameworks

Technical Leadership

• Ability to provide technical direction and mentorship to cross-functional data science and engineering teams, driving architectural decisions and best practices across the AI stack
• Effective at translating business problems to AI solutions that can scale

Other Attributes and Skills

• Brings creative, first-principles thinking to complex problems, confidently challenging established processes and conventions when better approaches exist
• Thrives in fast-moving, ambiguous environments, demonstrating sound judgment and adaptability as AI technologies and organizational priorities rapidly evolve
• Actively tracks cutting-edge developments in AI research — including latest publications, open-source releases, and emerging architectures — and synthesizes relevant advancements into actionable engineering insights
• Demonstrated ability to rapidly prototype and evaluate new AI capabilities, translating state-of-the-art research into proof-of-concepts that inform product and platform strategy
• Strong AI measurement skills with experience designing evaluation frameworks, benchmarks, and metrics for model quality, fairness, robustness, and business impact
• Ability to define and track experimentation rigor — A/B testing, offline vs. online evaluation, and model monitoring in production environments

Subsidiary:

PayPal

Travel Percent:

0

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. All communication regarding your application will come from official PayPal email domains. If you suspect fraudulent activity, please report it immediately.  To learn more about how to identify and avoid recruitment fraud please visit https://careers.pypl.com/contact-us. 

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. We strive to create a flexible, balanced work culture with a holistic approach to benefits, including generous paid time off, healthcare coverage for you and your family, and resources to create financial security and support your mental health.

Who We Are:

Click Here to learn more about our culture and community.

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.  In addition, PayPal will provide reasonable accommodations for qualified individuals with disabilities.  If you are unable to submit an application because of incompatible assistive technology or a disability, please contact us at [email protected].  

Belonging at PayPal: 

Our employees are central to advancing our mission, and we strive to create an environment where everyone can do their best work with a sense of purpose and belonging. Belonging at PayPal means creating a workplace with a sense of acceptance and security where all employees feel included and valued. We are proud to have a diverse workforce reflective of the merchants, consumers, and communities that we serve, and we continue to take tangible actions to cultivate inclusivity and belonging at PayPal.

Any general requests for consideration of your skills, please Join our Talent Community.

We know the confidence gap and imposter syndrome can get in the way of meeting spectacular candidates. Please don’t hesitate to apply.