To efficiently handle the invocation of vendor applications and retry requests that generate timeout errors, the most performant way is:

Scatter-Gather Scope: Use a Scatter-Gather scope to invoke each vendor application in parallel. This approach allows the API to send requests to both vendors simultaneously, reducing overall processing time.

Until-Successful Scope: Inside each route of the Scatter-Gather scope, use an Until-Successful scope to handle retries. The Until-Successful scope will retry the request in case of timeout errors until the request succeeds or the maximum retry limit is reached.

This combination ensures that the API can handle intermittent network issues efficiently while minimizing redundant transactions and maximizing performance.

References

MuleSoft Documentation on Scatter-Gather Scope

MuleSoft Documentation on Until-Successful Scope and Error Handling