OR vs XOR gateway

I have been told by Appian professional services, ALWAYS use XOR and not OR for all scenarios. OR might get deprecated in future as well. If we have a path where OR gets hit again and again we have seen issues that it does not work properly and XOR had no issues. I would also suggest your account rep and get the right answer directly from Appian Engineers/Experts.

Hello Himanshu, It is very well explained in the links provided below,
XOR - forum.appian.com/.../XOR_Node
OR - forum.appian.com/.../OR_Gateway

However to give you a gist,
- XOR Gateway: there are can multiple conditions configured but the first condition to be satisfied (returning a true) will take precedence and that particular flow will proceed. So it is like an - if..else ifs..else statement
In case of OR - there can be multiple conditions and all conditions satisfying will flow. So it is like a bunch of if statements and all those conditions returning a true will flow through.
As per the Best Practise we should be avoiding the usage of OR Gateway provided there is a valid business requirement (design) which makes/mandates us to use it.
Hope this helps.

Real World Scenarios:
XOR: Let us suppose you are buying stuff at a grocery store and you have coupons for the same.
Once all the items are added the cashier is provided with 2 options(buttons) 'Proceed with Payment' and 'Add Coupons', so it is an either or statement, the flow is different on click of each option (if one proceeds the other should not), here we can use an XOR gateway. Because we need only one flow to proceed either to pay or to add coupons.

For an OR Gateway: Suppose in a bank one wants to get a credit card, a debit card, open a fixed deposit, open a foreign exchange account and so on.. all of which are mutually exclusive of each other, one may choose any (1 or more) of the options provided, in this case one may use an OR Gateway and have different flows based on the options selected.

Please treat the above given scenarios as examples and when encountered in real life the requirements around it may dictate the usage of the appropriate gateway.

Excellent explaination Shrutij.Thanks a lot.

well explained shruti.

Good Explaination Sruthi

Yes, shrutij.

Very simply:

Do you want all flows that apply to this instance to happen simultaneously in parallel, or do you want the process to continue as soon as any merging flows arrive at this point? OR gateway

Do you want multiple parallel flows to begin at this point with no restrictions, or do you want the process to wait here until all incoming merging flows reach this point (wait until parallel processes are all done)? AND gateway

Do you want one and only one process flow to move forward and make a mutually exclusive decision about the only path the flow should take from here? XOR gateway (Yes you almost always use this one. You could go months or years without ever using the others)

Do you have to manage multiple incoming and outgoing flows at the same time using the same gateway? COMPLEX gateway

OR All cases that evaluate true result in a process flow, at minimum none, at most all of them.

XOR Only the first condition that evaluates true will be selected and move forward.