FreshBooks and GPSWOX Automation System

Hi,

I’m looking for a developer to build a small automation system connecting FreshBooks and GPSWOX.

Here is the goal:

• My clients receive monthly invoices via FreshBooks (recurring invoices)
• They pay through the FreshBooks invoice link
• After payment is completed, the system should automatically update their access in GPSWOX

IMPORTANT BUSINESS LOGIC:
Clients are on a 1-year contract. If they miss payments, they must pay ALL outstanding months before access is restored.
So the system must:

Check total outstanding balance (not just one invoice)
Only reactivate/extend access when FULL balance is paid

PAYMENT SETUP:
• FreshBooks payment methods must also be configured (Stripe / PayPal / credit card)
• Clients should be able to pay directly from the invoice
• Please set up and connect the payment gateway correctly

TECHNICAL REQUIREMENTS:
• Use FreshBooks API or webhook to detect when an invoice is paid
• Build a small backend (Node.js, PHP, etc.)
• Connect to GPSWOX API (update-client or correct endpoint)
• Update user/device access (reactivate / extend plan / expiration)
• Map FreshBooks clients to GPSWOX users

NICE TO HAVE:
• Simple dashboard/log to track payments and actions
• Error handling if API fails

Please let me know:

Your experience with APIs/webhooks
Which stack you recommend
Estimated time to complete

I want something simple, reliable, and fully automated.

Thank you.