I found the swagger-ui. But the only functionality I can imagine to do this job (I found) was the application patch method (swagger-ui#operation/Patch). But I find no explenation how to do it.
The explenation I found is for the cli tool of argocd (https://argoproj.github.io/argo-cd/user-guide/parameters/) which does not really help me.
Any idea?
Kazanki's answer does not address the question. While I agree that it may be an "anti-pattern", there are still times when this is desirable. For example, not wanting to maintain multiple sets of helm charts that would be identical other than for a single value (in my case, the ingress hostname).
This update can be done using argocd cli. Example:
argocd app set <appname> -p ingress.hostname=<new value>
I've yet to find out how to do this with REST but would very much like to know as well.
The whole point of adopting GitOps is to use Git as a single source of truth.If you want to change your application with ArgoCD you are expected to commit your change to the Git repository watched by ArgoCD.
Changing manually values via REST APIs is against GitOps.