Software Engineer (Senior)
About the role
Senior software engineer role at Pax, an AI-native operating system for global trade. Opportunity to own major product areas, design durable APIs, build across the stack, and mentor others in a high-stakes, regulatory domain.
Responsibilities
- Own major product areas end to end, from customer problem and technical design through implementation, launch, and iteration
- Design durable APIs, data models, workflows, and system boundaries for products operating on high-stakes financial and regulatory data
- Build across the stack, including backend systems, data pipelines, AI-powered workflows, and polished customer-facing interfaces
- Turn complex regulations and messy trade data into products that feel simple and reliable
- Work directly with enterprise customers to understand their operations, identify the real problem, and ship solutions quickly
- Establish technical direction while making pragmatic decisions about speed, quality, and long-term maintainability
- Raise the engineering bar through thoughtful design, strong execution, clear communication, and mentorship
- Help shape our engineering culture, architecture, hiring, and technical roadmap
- Build with large language models where they create real leverage and use deterministic systems where accuracy demands them
Qualifications
- 3+ years of experience (implied senior level)
- Strong record of building and shipping meaningful software at a high-growth startup or demanding technical environment
- Led substantial projects from problem to architecture, implementation, launch, and iteration
- Deep backend architecture focus with emphasis on product quality and user experience
- Experience with large language models and evaluating reliability and human oversight
- Ability to work with ambiguity and create structure
- Excellent communication with technical teammates, founders, customers, and domain experts
- Has substantial experience with React, Next.js, FastAPI, SQLModel, PostgreSQL or comparable frameworks
- Experience with global trade or customs compliance not required; ability to learn difficult domains is valued
Skills
Benefits
- Direct exposure to customers and impact on company direction
- Ownership and influence early in a startup
- Opportunity to shape engineering culture and technical roadmap
- Challenging, high-stakes domain with meaningful business impact
About Pax
AI Broker for Tariff Refunds
Pax uses AI to automate tariff refunds (aka duty drawback) for retailers and manufacturers. We launched 4 weeks ago and have ~$200K in contracts. Each year, 80% of eligible refunds—equivalent to $15B—go unclaimed. Pax is the first AI-powered broker helping brands under $50M reclaim 3-5% of their revenue. Our algorithms generate 15% more refunds than the industry leader and reduce processing time by 99% with AI. We are two technical founders: Penny got her PhD from MIT and, and was a former research scientist at Amazon & Flexport, where I encountered the problem firsthand. Chris is a second-time founder and former software engineer at Amazon, Brex, and TikTok.
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