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. Senior Software Engineer  The Sr. Software Engineer designs solutions and delivers complex features for our product platforms using AI tools throughout the development lifecycle. As a senior member of a small, collaborative pod,this position is accountable for complex features end-to-end---leveraging AI assistance for specification, implementation, quality validation, deployment, and post-deployment support while ensuring rigorous quality outcomes at each stage. The Sr. Software Engineer interfaces with Technical PMs and fellow engineers to deliver scalable SaaS products with high velocity. This position drives evolution of AI-assisted development practices, mentors team members on effective AI tool usage, and shares knowledge across pods WHAT YOU'LL DO * Own end-to-end specification quality for complex features – ensure specs are comprehensive, unambiguous, and address all edge cases and non-functional requirements * Lead AI-assisted implementation for complex features, ensuring high-quality outcomes * Collaborate with Technical PM to translate complex product requirements into detailed technical specifications * Use AI coding tools (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 * Design performant software with a DevOps mindset that will scale as our volumes increase * Design and implement REST APIs following established patterns * Mentor engineers on effective AI tool usage, spec writing * techniques, and code review practices * Share knowledge and experience across your pod and other teams * Drive improvements to AI-assisted development practices including spec templates, prompt patterns, and validation workflows * Lead technical decisions and own domain expertise within your pod\'s area * Support and maintain both UI and backend services within your pod\'s domain Qualifications * Bachelor\'s degree in Computer Science (or equivalent experience), along with a firm understanding of data structures and scalable software design * 5+ years of relevant software engineering experience designing and implementing scalable SaaS software * Strong ability to write code in Java, JSP, Node.js, XML technologies * Proven ability to code/support HTML5, CSS/Sass, Angular, React, TypeScript/Javascript, and other web technologies * Ability to design and implement REST APIs * Strong understanding of SQL and relational databases, such as SQL Server or MySQL * Well-honed skills in source control management using Git or similar * Demonstrated experience working with AI coding assistants (Claude Code, Windsurf, or similar) * Strong collaboration and verbal communication skills with ability to work closely with Technical PMs, pod members, and cross-functional teams * Strong code review skills with ability to validate correctness and identify issues in AI-generated and human-written code * Experience mentoring engineers through code review, pair programming, or technical guidance Preferred * Experience with spec-driven, agentic AI workflows where engineers delegate autonomous tasks to AI tools and provide guidance and oversight * Knowledge of NoSQL data stores, such as MongoDB or DynamoDB * Knowledge of Elastic, Apache Solr and Lucene * Experience with AWS, Azure or a similar cloud platform * Understanding of testable application design principles * Experience leading development process improvements or workflow optimization * Track record of driving adoption of new tools or practices across teams