Email Detective

See which ESP sent any email in Gmail. Detects 100+ providers and shows SPF/DKIM/DMARC authentication.

Ever wonder which email marketing tool a company uses? Email Detective tells you instantly. Open any email in Gmail and see a "Sent via Mailchimp" (or Brevo, HubSpot, Klaviyo, etc.) badge right on the subject line. Click it for details: vendor website, authentication status (SPF, DKIM, DMARC), and whether a shared or dedicated IP address was used. WHAT IT DETECTS: -100+ email service providers across marketing platforms, newsletter tools, CRM systems, and transactional email services -Detects Mailchimp, Brevo, HubSpot, Klaviyo, Salesforce MC and many more -Infrastructure providers like SendGrid and Amazon SES, with smart detection that shows the actual marketing platform when possible FEATURES: -Instant ESP detection when you open any email -Clickable badge with ESP details popup -Email authentication checker (SPF/DKIM/DMARC) -Shows whether it's a shared or dedicated IP (where it can be detected) -Works in inbox list view for previously opened emails -100% private: all data stays in your browser PERFECT FOR: -Email marketers researching competitors -Agencies evaluating client tech stacks -Deliverability specialists checking authentication -Anyone curious about the tools behind the emails they receive Built by EmailTooltester.com, the independent email tool review platform with 15+ years of testing experience. Free. No account required. No data collected. Changelog: v1.3.0 -New: now shows whether a sender is using a shared or dedicated IP address. This helps you understand the sending setup behind any email at a glance. -Perform a deeper IP reputation lookup by opening Talos (popup includes a direct link now) -Added more ESPs (Pipedrive Campaigns and Connectif) -Improved pattern matching for ActiveCampaign, Brevo, and CleverReach v1.2.3 -New ESPs: Added Seguno and Lettermint -Fixed: certain Braze customers were detected as SparkPost. -Fixed: False positive Iterable detection -About panel in the popup added v1.2.2 - Fixed false positives for 3 ESPs - Added/Improved detection for Iterable and Acoustic v1.2.1: Added Magnews and Inboxroad ESPs Improved detection for MailerLite, GetResponse, and Ghost Pro Reduced false positives in body scanning v1.2.0 New: ESP Collection tracker in the popup. See how many of the 100+ providers you've spotted so far Reduced false positives: body scanner now only uses tracking domains, ignoring editorial links to ESP websites Fixed Substack emails incorrectly showing as Mailgun Added new ESPs: Maileroo, Mailtrap, PHPMailer, Strato Infrastructure ESPs no longer override app-level detections