Staff Software Engineer (Backend) - AI Infra

Innovate with purpose

At BILL, we believe in empowering the businesses that drive our economy. By replacing outdated financial processes with innovative tools, we help businesses—from startups to established brands—make smarter decisions and gain control of their operations. And we don’t stop there: we’re creating the future of financial automation so businesses can spend more time on what matters.

Working here means you become part of a vision-driven team that’s ready to tackle challenges and build cutting-edge solutions. We value purpose, drive, and curiosity—and we thrive in a fast-paced, ever-changing environment. Whether in one of our offices in San Jose, CA, Draper, UT, or working remotely, BILLders collaborate to deliver real impact for businesses that need more time in their busy weeks.

At BILL, we listen, learn, and lead—fostering collaboration and a drive for continuous growth. We’re committed to building a diverse and inclusive workplace that values each person’s unique skills and experiences. Even if you don’t meet every requirement, we’d love to hear from you—you might be just what we’re looking for, whether in this role or another.

✨ Let’s give businesses more time for what matters.

Make your impact within a rapidly growing Fintech Company

Join our AI Infrastructure team at the forefront of transforming financial operations for small and mid-sized businesses, which form the backbone of the U.S. economy, contributing to about 1% of the U.S. GDP. Our team is the powerhouse behind a diverse range of AI models — from sophisticated credit models and advanced document understanding to intelligent virtual assistants and groundbreaking new projects on the horizon. 

As a Staff Software Engineer, you'll play a pivotal role in shaping the future of fintech by developing cutting-edge solutions that streamline and enhance financial operations. This role offers a substantial scope for impact, allowing you to contribute directly to the success of millions of businesses while working at the intersection of AI, finance, and technology. You will define and execute architectural strategies that address long-term business and technical challenges. You'll have the opportunity to lead initiatives, drive innovations, and deploy models that save our customers time and effort, all within a dynamic, fast-paced environment that values high energy, cross-functional partnership, business acumen, and a strong sense of ownership.

We’d love to chat if you have:

• Advanced Degree in Computer Science, Engineering, Mathematics, or a related field, ideally, with a focus on Machine Learning/AI
• Demonstrated expertise in designing, implementing, and deploying scalable machine learning models, especially in the backend
• Experience with low latency systems, document understanding/generation, and virtual assistants is highly valued
• Skilled in integrations to ingest data sets from various data sources
• Experience in model evaluation frameworks to track and improve product/system performance, quality, data management and accuracy
• Develop, test, and refine prompts for a variety of use cases, ensuring high accuracy and relevance in generated outputs
• Experienced in integrating various SOTA LLM solutions (GPT, Claude, Gemini, etc)  into existing or new applications
• Contribute to the development of a scalable framework for prompt engineering, promoting reuse and knowledge sharing across different business units
• Stay up-to-date with advancements in Generative AI technology and contribute to strategic decisions on tool and platform selection
• Document prompt engineering processes, best practices, and use case outcomes to build a comprehensive prompt optimization solution
• Demonstrated expertise in fine tuning Large Language Models (LLMs) to drive model quality further
• Strong coding skills in Python, Java, or similar, along with experience in ML frameworks (e.g., PyTorch) and cloud services (e.g., AWS, GCP)
• Knowledge of CI/CD pipelines and MLOps principles
• A track record of successful cross-functional partnerships, with the ability to lead and inspire teams towards achieving shared goals
• Innovative Mindset: A passion for staying on the cutting edge of ML/AI technology, with a drive to explore and implement novel solutions
• Ownership and Drive: Exceptional problem-solving skills and a proactive approach to tackling challenges, taking ownership from concept through to deployment

What’s in it for you? 

Redefining how businesses automate their work is a fast-paced, exciting, and fun environment. But we also have benefits and perks to ensure the magic isn’t only experienced by our customers, but by our employees as well. 

Here is a preview of some of the amazing benefits here at BILL:

• 100% paid employee health, dental, and vision plans (choose HMO, PPO, or HDHP)
• HSA & FSA accounts 
• Life Insurance, Long & Short-term disability coverage
• Employee Assistance Program (EAP)
• 11+ Observed holidays and wellness days and flexible time off 
• Employee Stock Purchase Program with employee discounts
• Wellness & Fitness initiatives
• Employee recognition and referral programs
• And much more

Don’t believe us? Check out our culture, benefits, and teams on our career site, LinkedIn Life, or YouTube pages.

BILL is an Equal Opportunity Employer that values diversity and inclusion. We believe our best ideas come from the unique stories, perspectives, and experiences of our team members. We welcome people of all backgrounds, abilities, and identities to bring their authentic selves and contribute to our culture.

We are committed to a transparent, inclusive hiring process that reflects our values. If you need accommodations at any stage, please contact interviewaccommodations@hq.bill.com.

Our Applicant Privacy Notice describes how BILL treats the personal information it receives from applicants.