Senior Full-Stack Engineer (Python / React) — US or Canada only

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.