Sébastien,
If the 3rd party app has the ability to host an HTML snippet then you could potentially just use the Genesys Cloud Embeddable Framework component to offer Genesys agent functionality from right within that web application:
https://developer.genesys.cloud/platform/embeddable-framework/. This the same component that Genesys and our AppFoundry partners use to embed Genesys agent functionality into CRMs like Salesforce, Zendesk, Dynamics, etc.
You could decide to only implement the clickToDial (https://developer.genesys.cloud/platform/embeddable-framework/actions/clickToDial) part of the Embeddable Framework if you wanted to. These calls will be ACD queue calls, so the agent will have to select the queue before the call is placed.
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Jim Crespino
Senior Director, Developer Evangelism
Genesys
https://developer.genesys.com------------------------------