How to publishing process models as web services

Do you want to expose an existing Appian process as a web service to be called by other systems?

OR

Do you want to call a web service exposed by another system from Appian?

Documentation: docs.appian.com/.../Call_Web_Service_Smart_Service.html

@Stefen Helzle

Thank you for your reply.

I want to expose an existing appian process model as a web service to be called by other systems.
The reason I did that is because I wanted to customize the error message of the Web API's response status code.
eg.【status code:401、Unauthorized】→【status code:401、customize error message】
Is my idea correct?

You write "The reason I did that". But what is "that"?

The most common, and best, way to expose a process model to the outside is using a web API. Find the documentation here: docs.appian.com/.../Web_APIs.html

"The reason I did that " mean "using <Call Web Service Smart Service> in process model".
the purpose of using call web service smart service in process model is want to get web api response status code and need to customize the error message of the web api response status code .Especially status code 401 ,403.

Using web api cannot customize the error message of the web api status code 401,403

It is a real challenge trying to follow you ...

You cannot customize the error message for events handled by the Appian authentication and authorization logic. And there is a good reason for this. It is about the code (401, 403), but not about any text in that message! That text can be in any language and tell you complete nonsense, as long and the codes are used correctly.

Thank 

Thank