Obtaining HubSpot Client ID and Secret
Open HubSpot Developer and sign into your account, or create a new one.
From within the home of the Developer account page, go to "Manage apps".
Click "Create app" button top right.
Fill in any information you want in the "App info" tab
Go to tab "Auth"
Now copy the Client ID and Client Secret to your .env file into the
Set the Redirect URL for OAuth
<Cal.com URL>/api/integrations/hubspot/callbackreplacing Cal.com URL with the URI at which your application runs.
In the "Scopes" section at the bottom of the page, make sure you select "Read" and "Write" for scope called
Click the "Save" button at the bottom footer.
You're good to go. Now you can see any booking in Cal.com created as a meeting in HubSpot for your contacts.