According to Live Direct Marketing's daily Tranco top-1M scan (July 13, 2026), Exclaimer (signatures) is the email service provider (ESP) for 2,665 domains — 0.43% of 617,702 SPF-publishing domains. Detection method: include: mechanisms in the SPF record.
Exclaimer is a cloud-hosted signature management platform that allows organizations to centrally design, deploy, and maintain email signatures across their user base. Operated by Exclaimer Ltd (now part of Upland Software), it typically integrates with Microsoft 365 and on-premises Exchange environments via SMTP or API plugins, and its presence becomes visible in email infrastructure when organizations add Exclaimer's SPF include mechanisms to their authentication records.
Exclaimer's presence is strongest among smaller and mid-market organizations rather than the largest brands, with heavy concentration in the .com domain space and frequent co-occurrence with Microsoft 365 environments. For email senders and administrators, this means Exclaimer is a common middleware component that affects how email authentication is configured and how messages are routed — not a high-risk provider, but one whose role in your SPF and SMTP chain is worth understanding for deliverability troubleshooting.
| Tranco rank band | Domains | Share of its base |
|---|---|---|
| Top 1,000 | 1 | 0.0% |
| Top 10,000 | 13 | 0.5% |
| Top 100,000 | 212 | 8.0% |
| Top 1,000,000 | 2,183 | 81.9% |
| Unranked | 256 | 9.6% |
| TLD | Domains | Share | |
|---|---|---|---|
| .com | 1,342 | 50.4% | |
| .nl | 227 | 8.5% | |
| .org | 158 | 5.9% | |
| .co.uk | 134 | 5.0% | |
| .de | 110 | 4.1% | |
| .be | 62 | 2.3% | |
| .com.au | 48 | 1.8% | |
| .net | 41 | 1.5% | |
| .org.uk | 38 | 1.4% | |
| .ca | 32 | 1.2% |
Cross-tabulated from the same daily snapshot — the other email services seen on the same 2,665 domains.
| Type | Service | Domains | Share of Exclaimer (signatures) users |
|---|---|---|---|
| Mailbox | Microsoft 365 | 1,702 | 63.9% |
| Mailbox | Mimecast | 249 | 9.3% |
| Mailbox | Google Workspace | 134 | 5.0% |
| Mailbox | Unknown / Other | 129 | 4.8% |
| Mailbox | Proofpoint | 109 | 4.1% |
| Mailbox | Barracuda | 94 | 3.5% |
| ESP | SendGrid (Twilio) | 426 | 16.0% |
| ESP | Salesforce | 379 | 14.2% |
| ESP | HubSpot | 351 | 13.2% |
| ESP | Amazon SES | 345 | 12.9% |
When an organization deploys Exclaimer, it typically adds Exclaimer's SPF include mechanism to its own SPF record, creating a chain where the originating mail server's domain includes a third party's infrastructure in its authentication policy. This has downstream implications: forwarding systems may break SPF alignment, and recipients' mail filters will see the signature-rendering hop as part of the mail path. Understanding whether Exclaimer is in your SPF chain is essential for diagnosing authentication failures and for setting realistic expectations around mail forwarding and alternative delivery paths.
See the full Exclaimer (signatures) data page (KPI cards, trend, sample domains) →
Exclaimer is a signature management service that renders and injects email signatures, typically integrated with Microsoft 365. It appears in SPF records when your organization uses it — its presence is normal infrastructure, not a deliverability risk.
2,665 domains in the Tranco top-1M use Exclaimer (signatures) as their email service provider (ESP) as of July 13, 2026 (0.43% of SPF-publishing domains), according to Live Direct Marketing's daily DNS scan.
Exclaimer (signatures) accounts for 0.43% 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.
Exclaimer (signatures) is growing — its share moved +0.01 pp over the last 30 days (as of July 13, 2026).
Exclaimer (signatures)'s largest TLD is .com (50.4% of its domains); it appears across 107 TLDs in total.