Integration of Square with Third-Party Platform

Questions
1

Hello Square Developer Team, I am currently building an integration where a third-party system handles order creation and payment processing (outside of Square), and I want to sync those orders into Square for reporting and POS visibility.

My use case is:

  1. Orders are created in a third-party system
  2. Payments are processed outside of Square (e.g., Stripe or another gateway)
  3. I want to push these orders into Square using the Orders API / API integration
  4. The goal is to keep Square updated for inventory, reporting, and fulfillment tracking
  5. Along with this, I am using Membership Anywhere to manage a digital membership card system, where members receive a scannable digital card, access benefits, and have their membership status managed centrally

I have a few questions:

  1. Is it supported to create Square orders when payment is processed outside of Square?

  2. If yes, how should the order/payment status be structured (e.g., “paid externally”) so it doesn’t break reporting or appear as “Custom Amount”?

  3. What is the recommended API flow for syncing:

  • Order creation
  • Payment mapping (external payment reference)
  • Webhook tracking for fulfillment updates
  • Are there any limitations or best practices when using Square purely as a “system of record” while payments are handled externally?

Any guidance, examples, or documentation links would be really helpful.

Thank you!

2

Hi @grace , thanks for reaching out.

  1. Yes, you can take payments processed outside of Square

  2. Set the source_id to EXTERNAL . Here are some docs on how to do this: https://developer.squareup.com/docs/payments-api/take-payments/external-payments

  3. Yes, this flow looks good. You’ll need to create the order first, then associate the payment to this order. In general, yes, you can use Square purely as a system of record with the customer interactions and flows coming from other systems.