Quick share: I made a free Chrome extension that shows you which ESP sent any newsletter in Gmail.
So when you get, for example, a competitor's newsletter, you instantly see if they're on Klaviyo too, or Mailchimp, ActiveCampaign, or something else.
It also tells you if they're on a shared or dedicated IP and whether their authentication (SPF/DKIM/DMARC) is set up correctly. Handy if you want to check how you or other senders have their setup configured.
It's free on the Chrome Web Store. No data leaves the browser. Feedback is welcome.
