I built a free Chrome extension that shows which ESP sent any email in Gmail
I spend a lot of time looking at what ESPs companies use. Got tired of digging through the email source every time, so I built a free Chrome extension that does it automatically.
It sits inside Gmail and shows you which platform sent each email. Mailchimp, Brevo, HubSpot, Klaviyo, whatever. It detects 140+ ESPs and also shows SPF/DKIM/DMARC authentication status. It also shows if HTML builders like Stripo and Beefree have been used.
In addition, it can also check BIMI and whether a VMC exists. You'll also see the sender IP and whether it's a shared or dedicated IP setup.
It works by scanning the email source for ESP fingerprints (tracking domains, header patterns, sending infrastructure). No personal data leaves your browser.
Deliverability folks have been the most enthusiastic users so far, which is why I'm posting here. Please let me know if there's any information you would like to see in addition.
The extension is called Email Detective and it's free on the Chrome Web Store.
