Lead Software Engineer (C++)

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.

Lead Software Engineer

Job Summary

The Lead Software Engineer designs solutions and delivers backend features for our product platform using AI tools throughout the development lifecycle. As part of a small, collaborative pod, this position is accountable for features end-to-end-leveraging AI assistance for specification, implementation, quality validation, deployment, and post-deployment support while ensuring quality outcomes at each stage. This is primarily a backend role focused on high-throughput data ingestion, PDF processing, and working with large datasets. The Software Engineer interfaces with Technical PMs and fellow engineers to deliver scalable, performant services with high velocity. This position also helps evolve our AI-assisted development practices and mentors Associate Engineers on effective AI tool usage.

Job Responsibilities

• Own specification quality for assigned features - ensure specs are complete, unambiguous, and include acceptance criteria and edge cases
• Collaborate with Technical PM to translate product requirements into detailed technical specifications
• Use AI coding tools (Claude Code) to generate implementations from specifications
• Design and build data ingestion pipelines that reliably process large volumes of structured and unstructured data
• Implement PDF parsing, extraction, generation, and manipulation capabilities for high-volume document workflows
• Design performant, memory-efficient software that scales as data volumes increase, with a DevOps mindset
• Review AI-generated code and peer contributions for correctness, security, performance, and architectural alignment
• Validate AI-generated tests and ensure comprehensive test coverage
• Design and implement REST APis following established patterns
• Optimize queries, schemas, and storage strategies for large relational datasets
• Mentor Associate Engineers on effective AI tool usage and spec writing techniques
• Share knowledge and experience with the team
• Help evolve Al-assisted development practices including spec templates, prompt patterns, and validation workflows
• Take ownership of domain knowledge within your pod's area
• Support and maintain the backend services within your pod's domain
  
  

Qualifications

Required

• Bachelor's degree in Computer Science (or equivalent experience), along with a firm understanding of data structures and scalable software design
• 10+ years of relevant software engineering experience designing and implementing scalable backend software in a product-centric environment
• Strong ability to write production code in C++
• Experience developing on Windows with C++ using Windows development libraries (e.g., Win32 API, MFC, or ATL)
• Strong ability to write code in .NET (C#)
• Strong ability to write code in Python
• Strong understanding of SQL and relational databases, specifically MySQL, including schema design and query optimization for large datasets
• Knowledge of NoSQL data stores, such as MongoDB or DynamoDB
• Experience building data ingestion and processing systems that handle high volumes of data
• Experience with PDF handling-parsing,extraction, generation, or manipulation-using established libraries or custom implementations
• Ability to design and implement REST APis
• Experience building and deploying software on AWS
• 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 and pod members to gather requirements and refine specifications
• Strong code review skills with ability to validate correctness and identify issues in Al-generated and human-written code
  
  

Preferred

• Experience with spec-driven, agentic AI workflows where engineers delegate autonomous tasks to AI tools and provide guidance and oversight
• Experience with performance profiling, memory management, and optimizing throughput for data-intensive workloads
• Experience with message queues or streaming platforms (e.g., Kafka) for ingestion pipelines
• Experience mentoring junior engineers