Letsignit email service provider (ESP)

According to Live Direct Marketing's daily Tranco top-1M scan (July 12, 2026), Letsignit is the email service provider (ESP) for 149 domains — 0.02% of 617,244 SPF-publishing domains. Detection method: include: mechanisms in the SPF record.

Key facts

Letsignit is an email signature management service that organisations use to standardise and control email signatures, branding, and compliance metadata across their mail systems. When deployed, it authenticates via SPF include mechanisms in the sending domain's DNS records.

Letsignit's footprint is concentrated among smaller organisations in the .com domain space, typically deployed alongside Microsoft 365. For mail administrators, this pattern means Letsignit represents a straightforward SPF configuration addition with no major reputation implications.

Where Letsignit sits in the Tranco ranking

Tranco rank bandDomainsShare of its base
Top 1,00000.0%
Top 10,00000.0%
Top 100,000149.4%
Top 1,000,00012483.2%
Unranked117.4%

Top-level domain split

TLDDomainsShare
.com7550.3%
.fr3724.8%
.org74.7%
.nl53.4%
.net32.0%
.se32.0%
.io32.0%
.cl21.3%
.dk21.3%
.co.uk21.3%

What Letsignit users also use

Cross-tabulated from the same daily snapshot — the other email services seen on the same 149 domains.

TypeServiceDomainsShare of Letsignit users
MailboxMicrosoft 36511073.8%
MailboxSophos Email74.7%
MailboxUnknown / Other74.7%
MailboxSelf-Hosted53.4%
MailboxProofpoint42.7%
MailboxBarracuda32.0%
ESPMailjet (Sinch)3120.8%
ESPBrevo (ex-Sendinblue)3120.8%
ESPSalesforce1610.7%
ESPSendGrid (Twilio)1510.1%

SPF authentication and signature-management platforms

Letsignit uses SPF includes to authenticate, adding a single DNS mechanism to the sender's SPF record rather than operating independent sending infrastructure. Because the service is concentrated among smaller organisations and deployed primarily as an add-on to Microsoft 365, it does not accumulate the high-volume reputation concerns that larger mail platforms might carry, making it a straightforward authentication component for organisations that use it.

See the full Letsignit data page (KPI cards, trend, sample domains) →

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Frequently asked questions

Does Letsignit appear in my mail authentication records, and is it a deliverability concern?

Letsignit is a signature management platform that adds an SPF include to your domain's DNS records. Because it operates primarily among smaller organisations, it represents a routine configuration element rather than a reputation risk.

How many domains use Letsignit?

149 domains in the Tranco top-1M use Letsignit as their email service provider (ESP) as of July 12, 2026 (0.02% of SPF-publishing domains), according to Live Direct Marketing's daily DNS scan.

Is Letsignit common enough to affect email deliverability testing?

Letsignit accounts for 0.02% of SPF-publishing domains in the top 1M. Whether you should seed a test mailbox there depends on how much of your audience it represents — the co-usage table above shows the services it appears alongside most.

Which countries or TLDs use Letsignit most?

Letsignit's largest TLD is .com (50.3% of its domains); it appears across 20 TLDs in total.

Other email service provider (ESP)s

Amazon SES (6.21%)SendGrid (Twilio) (4.75%)Mailgun (4.11%)Zendesk (3.87%)Mailchimp (3.69%)Mandrill (3.36%)HubSpot (3.18%)Salesforce (2.62%)Mailjet (Sinch) (2.13%)Cloudflare Email Routing (1.80%)