Stripe to Square Payment Integration Update

Looking for a Backend / Full-Stack Developer to Modify Payment Integration

I have a live website partstop.net. The current developer is unavailable and refuses to update the payment method (Stripe to Square), so I am looking for an experienced engineer who can take over the task, review the existing codebase, and modify or replace the payment integration.

Current Tech Stack:

Frontend: Pure HTML (no website builders, no visual editors)

Backend: Node.js + Express

Database: MongoDB

Scope of Work:

Review the existing Stripe payment implementation

Propose a stable and compliant alternative or rework the current integration

Implement and test the new payment solution Square

Ensure security, reliability, and scalability

Requirements:

Strong experience with Node.js / Express

Hands-on experience integrating payment gateways (Stripe, Square, or alternatives)

Ability to work with existing / legacy code

Good understanding of payment security and PCI compliance

Reliable, structured, and result-oriented

Additional Notes:

Existing production codebase

This is not an MVP or a website builder project

Long-term collaboration is possible for the right developer