Email Detective for Outlook: Identify ESPs & Check Authentication

Detects which of 140+ email services (ESPs) sent any email in Outlook web, plus SPF, DKIM and DMARC checks.

See which ESP sent any email in Outlook. Detects 140+ 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 Outlook on the web 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: -140+ 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 HTML builders like Stripo and BeeFree ---- Not using Outlook? We also have a version for Gmail: https://chromewebstore.google.com/detail/email-detective-for-gmail/jmflpchhakbogamlbfmlkglnpgfbhidl ---- FEATURES: -Instant ESP (email service provider) detection when you open any email -Clickable badge with ESP details popup -Email authentication checker (SPF/DKIM/DMARC) + BIMI and VMC -Shows whether it's a shared or dedicated IP (where it can be detected) -Works in your inbox list view for previously opened emails -Your email content never leaves your browser -Share anonymous meta data or opt out anytime in settings How to audit your own deliverability in seconds: -Send yourself a campaign from your own email marketing service. -Open it in Outlook, click the "Sent via" label, then "check authentication." -You'll see SPF, DKIM, DMARC and BIMI status laid out cleanly. Anything missing or failing is flagged. 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 personal data collected. Please note that the plugin also exists as a Gmail version (Email Detective for Gmail). Changelog v1.2.41 -Detects BonLoyalty and Nutshell -Fixed authentication checks failing for some French and Portuguese Outlook users -Fixed a bug where a missing DMARC record could show as unclear instead of flagged v1.2.33 -Detects Maileon and E-goi as ESPs, plus 4 more countdown-timer/live-content vendors: Sendtric, CountdownMail, MailTimers, and Motion Mail App v1.2.31 -More accurate delivery-time measurement v1.2.31 -More accurate detection for brands that use Intercom for both marketing and support emails. -Detection improvements. v1.2.30 -Detects forwarded emails, manual and auto-forwarded, across GMX/Outlook/Gmail/Yahoo/Apple Mail, and stops crediting the forwarder as the original sender. v1.2.28 -The activation screen now appears in Japanese, Spanish, French, Italian, Portuguese and Polish based on your browser language. v1.2.27 -New detections: Haihaimail, Blastmail, Easypromos -Removed the expired ActiveCampaign discount -Fixed a bug where the previous email's badge could stick when switching emails v1.2.26 -Added detection for ActionKit -Behind the scenes tracking additions v1.2.24 -Behind-the-scenes improvements v1.2.23 -Added TurboSMTP detection. DMARC warnings now trigger on missing records too. v1.2.19 -Improved support for a range of non-English languages -Behind-the-scenes improvements v1.2.14 -Fixed a bug for French users that triggered the immersive reader -Renamed Sarbacane / User.com / Positive Group to "Positive User" v1.2.12 -New detection for Inflection.io, Resend (when sent via Amazon SES), and IdoSell -Forwarded emails now handled correctly: shows the original sender's SPF result and labels the message as forwarded, instead of showing a false "pass" -Further detection improvements v1.2.8 -Smaller bug fixes and under the hood changes v1.2.2 -Extension doesn't freeze anymore after detecting many consecutive emails -No more false DMARC "passes" -Two false alarms cleaned up (rapidmail and Sarbacane were flagging when they shouldn't) -Now also spots two more tools: Creatio and Elastic Email v1.1.3 -MDirector and Revinate added to detection. -Fixed the popup sometimes closing when you clicked "More details" + some additional polish. -Discount links added for Beehiiv and Brevo. v1.1.2 -We now detect Edrone, a Polish e-commerce marketing platform. -Sharper detection for ExpertSender, Retarus, and Bloomreach -Behind-the-scenes work to keep detection reliable across Gmail and Outlook. v1.1.1 -We now detect 6 more email services (Lindris, XCAMPAIGN, EmailLabs, and Euromessage). Plus behind-the-scenes work so detection stays in sync across Gmail and Outlook. v1.1.0 -Sender tech, one click away. The email card now has a "More details" expand showing the sending setup: the MTA powering it, Return-Path, CSA certification (if existing), TLS, and the send date. -Sharper detection. More cleanup of plain domain names that could cause false matches. v1.0.25 -SPF/DKIM/DMARC/BIMI now check automatically when you open the popup on a detected email. No extra click needed. v1.0.23 -Popup now matches the Gmail version: ESP favicons, a stacked inbox vs junk placement bar, and an Authentication tab. -More accurate ESP detection: removed a batch of overly broad patterns that could tag the wrong provider. -Better authentication reads: fixed a case where a "From" address split across two lines made SPF/DKIM/DMARC show as failed when it actually passed. -Pepipost now labeled under its current name, Netcore. -Small polish on the in-email "Wrong detection?" report. v1.0.15 -Further detection improvements (new ESPs added) -Beefree SDK vs RGE Studio builder detection + the Postcards builder added -Other minor fixes v1.0.13 -Detection improvements. Previously detected labels won't disappear anymore. v1.0.10 -Various bug fixes and faster detection v1.0.4 -Minor improvements