eBay Messaging & Webhook Integration Support

My Python-Flask backend already authenticates with the eBay Sell APIs through OAuth and exposes a public webhook endpoint; now I need the last two pieces working reliably: full buyer-seller messaging and the Order Paid Webhook. Both are equally important to me.

Messaging
I hold active Trading API credentials, so the job starts at the point of wiring them into code. I want to both send and receive buyer messages through GetMyMessages and AddMemberMessageAAQToPartner, have them mapped back to the correct order in my database, and see concise, working Python examples that I can drop straight into the app.

Order-Paid Webhook
The destination and subscription must be created correctly so that the “order paid” topic reaches my Flask endpoint without raising errorId 195017. Once an event lands, the flow should automatically pull the order with the proper token scope and hand the payload off to my existing order-processing function.

Deliverables (release of payment hinges on these):
• Messaging: successful round-trip send/receive in my environment, with order correlation and sample code committed.
• Notifications: a live subscription that triggers on a sandbox & production sale, proves the endpoint works, and fetches the order details.

If you have deep experience with the Trading XML API, Notifications API, OAuth scopes, and Python-Flask webhooks, let’s wrap this up.