The field name TIBCO Cloud API Management Control Center, used for APIM or APIM-LE(Tethered) is:
Time to wait for a response from endpoint

The fields in Configuration Manager used for APIM-LE(Unthered) is:
Endpoint Response Wait Time

This article provides inputs on the wait time for a response from the backend.

All Supported Platforms

#SaaS
For traffic served in APIM(formerly Mashery Cloud/SaaS) the maximum value for this field is 120s. This is because:
- The idle-timeout of 120sec is enforced on the ALB level and will apply to all endpoints on it or domains CNAME'd to it.
- The 120sec limit is enforced at the kernel level of our infra and cannot be increased.

#Local
For traffic served in APIM-LE(formerly Mashery Local) this limit or the associated warning does not apply.
A value higher than 120s can be configured for such endpoints.


#Recommendations and Other Info
> We strongly recommend the value for Response Timeout be not more than 60 secs.
> If the backend is taking longer than 60 seconds then the API might not be well designed or might have resourcing issues. Just increasing the timeout might mask the root cause temporarily but will add load on the system and eventually resurface.
> Setting higher timeout values combined with high traffic for those endpoints can cause requests to queue up and other requests stuck at the bottom of the queue might start to timeout as worker threads would be waiting to get the response before dropping the connection to serve other requests. This could have a direct impact on traffic.
> Here is an excerpt from AWS docs that explains long running transactions:
--------------
For each request that a client makes through a load balancer, the load balancer maintains two connections.
The front-end connection is between a client and the load balancer.
The backend connection is between the load balancer and a target.

The load balancer has a configured idle timeout period that applies to its connections.
If no data has been sent or received by the time that the idle timeout period elapses, the load balancer closes the connection. To ensure that lengthy operations such as file uploads have time to complete, send at least 1 byte of data before each idle timeout period elapses, and increase the length of the idle timeout period as needed.
-------------