Software Engineer (Senior)

Senior Software Engineer Opportunity At PaxPax is the AI control tower for global trade. Enterprises like Verkada, Glossier, Yamaha, and Kodak use Pax as the intelligence layer for their trade-compliance operations: connecting fragmented data, continuously auditing transactions, preparing and filing claims, and recovering money that has quietly slipped away for years. We started with duty drawback, a $10B-per-year opportunity hiding in plain sight. Now, we're building the operating system for how enterprises manage trade compliance and recover every dollar they're owed.Our platform includes:Duty drawback: Recover tariffs paid on goods that are later exported, returned, or destroyed.IEEPA and reciprocal tariff recovery: Claim refunds associated with the latest wave of tariffs.Entry and export audits: An AI agent that reviews customs transactions line by line and catches errors before they reach U.S. Customs and Border Protection.This is only the beginning. Our goal is to build the complete control tower for global trade.Tariffs have become a board-level concern. Companies have faced rates ranging from 25% to 145%, creating an urgent need for software that can turn complex regulations and fragmented records into accurate, actionable decisions. There has never been a better time to make a tangible impact on real businesses.Pax was founded by people who lived this problem. Penny Chen, our CEO, holds a PhD from MIT and previously built optimization systems at Flexport and for Amazon's last-mile supply chain. Chris Le is a repeat founder who previously worked at Brex, TikTok, and Amazon, including on last-mile supply-chain optimization.We're well-capitalized, serve real enterprise customers, and are looking for a senior software engineer to take ownership of critical products and systems. This is an opportunity to join early enough to shape the company, its engineering culture, and the future of a $10B-plus industry.You might build systems that reconcile tens of millions of dollars in annual trade volume, interpret thousands of pages of federal regulations, transform customs documents into structured data, or help an AI agent audit every line of an import entry before it reaches the government.The ideal candidate:Has a strong record of building and shipping meaningful software at a high-growth startup or other demanding technical environmentHas led substantial projects from an ambiguous problem through architecture, implementation, launch, and iterationCan go deep on backend architecture while caring deeply about product quality and a crisp user experienceWrites reliable systems for complex, high-stakes workflows and knows where additional safeguards are necessaryIs excited to build with large language models, understands their limitations, and thinks carefully about evaluation, reliability, and human oversightMakes sound tradeoffs between speed, simplicity, and scalabilityCommunicates clearly with technical teammates, founders, customers, and domain expertsIs comfortable operating with ambiguity and creating structure where none existsActs without waiting for permission while knowing when a decision needs broader inputWants to own business and customer outcomes, not just codeHelps other engineers do their best work through mentorship, feedback, and strong technical judgmentHas substantial experience with technologies such as React, Next.js, FastAPI, SQLModel, PostgreSQL, or comparable frameworksExperience in global trade or customs compliance is not required. We care more about your ability to learn difficult domains, make good decisions, and build exceptional software.We're a small team by design. You'll have direct access to customers, meaningful influence over company direction, and ownership that would take years to earn at a larger organization.The problems are technically demanding, operationally important, and tied directly to customer value. Your work will help enterprises navigate global trade, remain compliant, and recover millions of dollars they would otherwise lose.This is early enough for your work to shape both the future of Pax and the industry we're transforming. We believe it can be the most fulfilling work of your career.We work together in person in San Francisco. Our office is focused, fast-moving, and full of energy. This is a hard requirement; the role is not remote.For immigration support, we can accommodate TN visas and eligible visa transfers. Due to timing constraints, we cannot sponsor new H-1B petitions.If you've built something you're proud of, we want to see it.Important: If you're a talented software engineer, apply.