Full-Stack, Backend Leaning, SWE

Summary

Affiniti is building a financial operating system for small businesses across America. The company is seeking a backend-leaning full-stack software engineer to own backend architecture, build reliable financial product systems, contribute to frontend development, and partner with product and design to deliver customer-focused solutions.

Responsibilities

• Own the backend architecture behind our product. APIs, data models, business logic, and the foundational decisions that determine how the product scales, performs, and stays reliable
• Drop into the full stack when it counts. Build frontend flows, wire up React components, and trace a bug from the browser to the database without waiting on anyone
• Build the systems that power complex financial products. The kind of backend where messy financial data, integrations, and business logic become simple, reliable experiences for customers
• Obsess over the details that separate software that works from software customers can trust: data integrity, API latency, failure modes, query performance, and the edge cases most engineers skip
• Partner closely with product and design to push past the requirements. Challenge assumptions, propose better solutions, and make sure what we build solves the actual customer problem — not just the technical specification
• Turn ambiguous user needs into clean, maintainable implementations. And advocate for the user in every technical decision

Skills

• 2+ years of production engineering experience
• Deep fluency in TypeScript and Node.js, with real opinions about API design, data modeling, backend architecture, and system reliability
• End-to-end ownership and strong product instincts. You can take a feature from idea to shipped without a frontend engineer holding your hand, and you care as much about the customer experience as the systems underneath it
• You know how to build with AI, not just use it. Tools like Claude Code, Codex, and other coding agents are a core part of your engineering workflow, and you know how to use them to dramatically increase your speed and output without outsourcing technical judgment
• A track record building complex, data-rich products backed by systems operating under real reliability and performance constraints
• Speed without the debt. You move fast without leaving behind the kind of backend mess that makes a codebase painful six months later
• High ownership. You take problems as your own and see them through — the mark of the people who thrive here
• Candidates must be currently authorized to work in their respective country
• For this role, we are considering U.S. candidates who are U.S. citizens, U.S. lawful permanent residents (Green Card holders), or individuals who otherwise currently hold valid authorization to work in the United States
• For Canadian candidates, we are considering Canadian citizens, Canadian permanent residents, or individuals who otherwise currently hold valid authorization to work in Canada
• Early-stage startup experience strongly preferred

Qualifications

Must Haves

• 2+ years of production engineering experience
• Deep fluency in TypeScript and Node.js, with real opinions about API design, data modeling, backend architecture, and system reliability
• End-to-end ownership and strong product instincts. You can take a feature from idea to shipped without a frontend engineer holding your hand, and you care as much about the customer experience as the systems underneath it
• You know how to build with AI, not just use it. Tools like Claude Code, Codex, and other coding agents are a core part of your engineering workflow, and you know how to use them to dramatically increase your speed and output without outsourcing technical judgment
• A track record building complex, data-rich products backed by systems operating under real reliability and performance constraints
• Speed without the debt. You move fast without leaving behind the kind of backend mess that makes a codebase painful six months later
• High ownership. You take problems as your own and see them through — the mark of the people who thrive here
• Candidates must be currently authorized to work in their respective country
• For this role, we are considering U.S. candidates who are U.S. citizens, U.S. lawful permanent residents (Green Card holders), or individuals who otherwise currently hold valid authorization to work in the United States
• For Canadian candidates, we are considering Canadian citizens, Canadian permanent residents, or individuals who otherwise currently hold valid authorization to work in Canada

Nice to Haves

• Early-stage startup experience strongly preferred

Benefits

• Offers Equity
• Reimbursed Relocation
• Free Lunch and Dinner (In NYC)
• Paid Technology Equipment Set Up
• Health, Dental, and Vision Insurance Fully Paid
• NYC (in office), Canada (remote)