Senior Full-Stack Engineer (Python / React) — US or Canada only
Posted
Location: candidates must be physically based in the US or Canada, with the right to work there. Full overlap with Central Time (US) business hours.
Format: long-term contract, full-time
Rate: $30–35/h (contractor, net)
Start: early–mid December 2026
About the project
A US fintech/payments SaaS company is looking for a Senior Full-Stack Engineer to join a very small product team. The product is an AI-driven platform that helps subscription merchants recover failed payments. You will work directly with the lead engineer, with minimal hand-holding.
What you will do
- Build frontend features in React / Next.js (deployed on Vercel)
- Build backend services in Python / FastAPI (microservices on AWS), including new payment provider integrations
- Integrate external services (payment processors, email delivery) - Work with the product's AI components on the integration level - Cover merchant requests and support tasks with the lead engineer
- Write your own automated tests
Requirements
- 5+ years of full-stack experience
- Strong React and Next.js
- Solid Python (FastAPI or similar)
- Microservices on AWS, CI/CD basics
- Experience integrating LLM / AI services into a product
- Fluent, confident spoken English: you will talk to the team and merchants daily
- Self-sufficient, clear written communication, calm with on-call style interruptions
Nice to have
- Payments / PSP integrations (Stripe, Braintree, Adyen)
- Temporal or other workflow orchestration
Hiring process Screening call → technical interview → client interview → possible short take-home (3–4 h) → contract.