Hey @PierrickPC! Thanks for reaching out. 
I don't know if it's the best option, but I'm mostly able to accomplish this using a custom component, as shown below. Note that I'm mocking the result of your API with a simple "File Input" component, which exposes the document data in base64.
I say "mostly" just because Chrome doesn't automatically open data URLs for security reasons, so I currently have to refresh the page in order to see the document. Using a blob URL should bypass this restriction. 
I've included the app JSON, as well: Sandbox.json (10.3 KB).
Hopefully this helps! Let me know if you have any follow-up questions.