Advanced REST Client is not able to read cookies set in Chrome browser. If you authenticated yourself in a Chrome tab cookies are not transferred automatically.
Now you can install ARC cookie exchange extension and synchronise cookies between Chrome and ARC. All cookies instantly will be available for the app when you install the extension.
How to use it?
First, install the extension:
Then open the app and use it. You won't see it working.
You can now authorise yourself in the regular chrome tab and then make authenticated request to the endpoint. All cookies with matched domain will be applied to the request automatically.
To stop cookie synchronisation and prevent them to be send with request just disable or remove the extension.
Is it safe?
Only Advanced REST Client (stable, beta, dev and canary) app is whitelisted to communicate with the extension. Other extensions or apps won't get any information about your cookies.
Naturally the extension will ask you for permission to access cookies. Access to cookies is per domain so the extension must have access to all domains. This is why you will see permission dialog to access your data on all websites.
Image source: https://www.flickr.com/photos/nonprofitorgs/10174117234
The image has been edited by the author of the app:
* removed background
* removed "sesame street" sign