Lead Software Engineer

Who We Are Finance leaders choose Billtrust to get paid faster, control costs, and maximize customer satisfaction. As the leader in B2B accounts receivable workflow and payment software, we provide the world’s leading brands with AI-powered solutions across the full AR lifecycle—from invoice presentment and payment processing to cash application and collections. With over 2,600 global customers, more than $1 trillion in invoice dollars processed, and a proprietary network of 13 million buyers, Billtrust delivers business value through deep industry expertise and a culture relentlessly focused on meaningful customer outcomes. We’re an AI-first company, not just in what we build for our customers, but in how we work. Across every function, our teams use AI tools daily to work faster, make better decisions, and deliver higher-quality outcomes. We hire exceptional people, give them cutting-edge AI capabilities, and measure success by the impact they create. If you want to do the best work of your career at the frontier of AI and fintech, Billtrust is the place to do it. Our Values Customers We relentlessly increase value for customer and do the right thing for them. Action We make ‘thoughtfully fast’ decisions, act quickly, cut through red tape, deliver progress not perfection, take ownership and accountability. Team Spirit We put the team ahead of ourselves, foster trust and respect, collaborate with passion, despise toxic politics, value our differences, and celebrate together. Innovation We challenge the status quo, experiment thoughtfully, and are novel and brilliant in what we create. Excellence We love to win, but we hate losing even more. We aspire to be the best and take pride in our work. When we fall short, we own it and come back stronger. About the Role The Lead Software Engineer is a critical role responsible for providing technical leadership within a domain-aligned cohort, guiding engineers in delivering quality, scalable SaaS products. You will leverage AI tools and co-worker agents such as Claude Code to specify, implement, validate, deploy, and support the most complex features end-to-end, focusing your expertise on architectural judgment, specification quality, and mentorship. This position partners closely with the Engineering Manager on cohort health and delivery, interfaces with Product Managers and stakeholders to translate business requirements into technical specifications, and plays a key role in building the cohort’s collective expertise. You’ll drive AI-assisted development practices and standards, mentor engineers across the cohort, and advise on tools and technologies that evolve our development organization. What You’ll Do Technical Leadership & Specification • Provide technical leadership within the cohort, guiding engineers in spec-driven, AI-assisted development • Own specification quality for the most complex features, ensuring specs are comprehensive, unambiguous, and address all edge cases and non-functional requirements • Collaborate with the Product Manager and stakeholders to translate business requirements into detailed technical specifications, and explain technical concepts to both technical and non-technical audiences • Other duties as assigned. AI-Assisted Implementation & Quality • Lead AI-assisted implementation for complex features, using AI coding tools such as Claude Code to generate implementations from specifications • Review AI-generated code and peer contributions for correctness, security, performance, and architectural alignment • Validate AI-generated tests and ensure comprehensive test coverage for complex scenarios • Drive AI workflow standards and best practices across your cohort, advise on tools and technologies to evolve our development organization, and share learnings with other cohorts Software Design, Delivery & Mentorship • Create software designs that consider both current and future requirements with a DevOps mindset that will scale as our volumes increase • De…