paypal-cli | CLI for PayPal REST APIs | REST library

The SDK

This is your problem line:

Simply ensure you're echoing/returning the whole response, or at least something with {"id":"......"}

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So from PHP, doing:

I see this is a client-side only integration for payment creation and capture, where then after that client-side capture you use a server=side AI call to get the details of the order. That's a very strange hybrid, one wonders why you didn't integrate 'Set Up Transaction' and 'Capture Transaction on the server side (and paired with the approval JS for a server side integration) to get all the benefits of that robustness, and then you wouldn't need an additional API call to get the details of the order since you would already have it after the server-side capture and be able to store it atomically. Basically, it seems you really should switch to that instead of this unnecessary hybrid you're trying to do.

But if you insist on doing weird and inadvisable things that nobody recommends, Order IDs like 7KM15574UC313712P weren't created by your server-side code, and so can't be accessed that way. What you can try instead is to look up the successful Capture ID (not Order ID) in the JS, from purchase_units[0].captures.id , and pass this actual PayPal transaction ID to your server code instead. Then use it to get the v2/payment capture object, which will use a different API/SDK call -- in your case, this one: https://github.com/paypal/Checkout-PHP-SDK/blob/develop/lib/PayPalCheckoutSdk/Payments/CapturesGetRequest.php

(But again, ideally this whole paragraph would be moot and you would pay more attention to paragraph #1)