Apple Pay on the Web — Platform Integrator: Is sub-merchant registration required when all transactions occur on a single hosted domain?

Hi Apple Pay Team,

We are building a QR-based payment platform and planning to integrate Apple Pay on the Web as a Payment Platform Integrator.

Our setup:

• We operate a single domain (e.g., pay.example.com) where all Apple Pay transactions take place
• When a customer scans a merchant's QR code, our hosted page opens with the Apple Pay button
• We process payments on behalf of multiple merchants (receivers), each with a separate merchant ID at our payment processor
• We want to use a single Payment Platform Integrator ID with one set of certificates (Merchant Identity + Payment Processing)
• The payment processor handles sub-merchant identification and settlement to the correct receiver via card network (Visa/Mastercard) sub-merchant fields

Our question:

Since all transactions happen on our single domain, is it mandatory to register each sub-merchant via the Apple Pay Web Merchant Registration API (/paymentservices/registerMerchant) and use their partnerInternalMerchantIdentifier in the payment session request?

Or is it acceptable to use our Platform Integrator's own merchant identifier for all payment sessions, given that:

• Only one domain is involved

• Sub-merchant identification is handled at the payment processor / card network level

• Our domain verification file is already hosted and verified

We would appreciate clarity on the correct approach before we proceed with our integration.

Thank you.