@CU10121822-0
'real time' here means synchronous execution. The external system sends a request, pauses, and waits while D365 F&O processes it immediately and returns a response within the same HTTP connection — typically within seconds.
The clearest way to understand it is by contrast
| Pattern | Mode | Caller Experience |
|---|
| Custom Service | Synchronous — real time | Caller waits and gets immediate response |
| DIXF / Data Entities | Asynchronous — staged | Data goes to staging, batch job processes later |
| Batch Jobs | Asynchronous — queued | Runs in background, caller does not wait |
Practical example — B2B e-commerce credit limit check:
A corporate customer clicks Place Order on an external web store. The store needs to know immediately whether the customer has sufficient credit in D365 before confirming the order.
Web store calls your D365 Custom Service endpoint passing customer ID and order total
Custom service queries CustCreditMax and live balances instantly inside F&O
D365 returns a JSON response within 1 second: {"Approved": true, "AvailableBalance": 15000.00}
Web store shows order confirmation immediately
If you used DIXF or a batch job here the customer would wait minutes staring at a loading screen while a background job picks up their file — that is why custom services exist for interactive, time-sensitive touchpoints.
if it helps , mark as verified
