Fullstack developer (Fintech / Payments Integration) - Part-time - North America

Overview

Aesthetronics is a SaaS platform serving spas, salons, and medical aesthetics businesses. We’re looking for a hands-on Full-Stack TypeScript Engineer to support a contract-based integration project.

The primary focus of this role is to lead and execute a complex payment processing (PayFac / fintech) integration into our existing, production SaaS platform. This is a time-bound project (~2 months) intended to free up our core engineering team.

Project Scope

• Integrate a payment facilitator (PayFac) platform (e.g., Phenix / Fenix or similar) into an existing SaaS product
• Work within an established codebase and live production environment
• Deliver a robust, secure, and scalable payment integration suitable for white-labeled SaaS use
• Collaborate closely with a small internal engineering team
• Estimated duration: ~2 months (contract)

Responsibilities

• Design and implement a complex payment processing integration
• Work across the full stack using TypeScript
• Integrate APIs, webhooks, and payment workflows
• Ensure security, reliability, and compliance best practices
• Write clean, maintainable, production-ready code
• Communicate progress clearly and work with minimal supervision

Required Skills & Experience

• Strong TypeScript experience
• Full-stack development experience
• Experience working on SaaS platforms in production
• Solid understanding of backend and frontend integration patterns
• Comfortable working independently on defined project deliverables
• Strong communication skills (English)

Nice-to-Have / Strong Preferences

• Experience with the MERN stack (MongoDB, Express, React, Node.js)
• Prior experience integrating fintech, PayFac, or payment processing platforms
• Especially white-labeled or embedded payments
• Stripe experience is helpful, but non-Stripe / more complex PayFac integrations are highly preferred
• Familiarity with fintech concepts, compliance, and secure transaction handling
• [Strongly preferred] Someone who has previously implemented a PayFac or embedded payments integration for a SaaS platform.