When using Transactional emails, you will have to use your unique API key to authenticate other applications to use this account.
To find the API key,
- Go to Admin Settings > API Key for Transactional Emails. This opens the page where you can find the API key.
- Copy the API key.
Use the API key while configuring transactional emails into your website.
To stop an application from using this account, reset your API key. Resetting will deny access to all the applications that are connected to your accounts. To grant them access, you will have to ‘Reset key’.