Email Detective — ESP Tracker

by EmailTooltester · crowdsourced from Email Detective users

Get Email DetectiveDetect any senderright in your inbox Gmail Outlook

1brands shown

127ESPs detected

123,498observations

556active users (30d)

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Importance Alphabetical Setup score Recently added

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Tech

Any AMP HTML builder BIMI

Volume

Any 10+ obs 50+ obs 100+ obs

Industry

Country

Signals

📧 Subscribers (97) 🚩 Gmail-flagged (94) 🐢 Slow delivery (91) ⚠️ Weak setup (78)

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Brand	Marketing	Other ESPs	Setup	Obs	Last seen
Helpscout helpscout.net ↗	HubSpot 79	—	58	79	2026-06-30

Top marketing ESPs →

Newsletter / campaign platforms, by brand count

Klaviyo

1543
Mailchimp

1005
Salesforce MC

922
HubSpot

762
Braze

410
Iterable

402
Kit

401
Brevo

381
Substack

353
ActiveCampaign

269
Customer.io

254
Beehiiv

228

Top transactional ESPs →

SMTP relay / infrastructure, by brand count

SendGrid

1743
Amazon SES

1568
Mailgun

770
SparkPost

410
Postmark

262
Salesforce CRM

129
Mailjet

116
Pepipost

65
EmailLabs

32
Resend

26
Inboxroad

25
SMTP2GO

22

Top HTML builders →

Email design tools, by brand count

Stripo

428
Beefree SDK

299
Unlayer

87
RGE Studio

15
Topol

14
Postcards

11

AMP for Email →

38 brands ship interactive AMP emails

Where emails landed (in Gmail) →

Averaged across 3,825 brands with 5+ placement observations

inbox 82.1%promotions 16.4%spam 1.5%

Spam placement is mostly driven by the sender (list quality, content, complaints), not the ESP.

Open Rate Accuracy →

17.9% of Outlook opens never fire the sender's tracking pixel (images blocked)

Based on 1,376 opens tracked. Open rates undercount real opens more than most senders realize.

How this works →

Anonymous, privacy-preserving observations from the free Email Detective extension. Read more