According to Live Direct Marketing's daily Tranco top-1M scan (July 12, 2026), Esker is the SaaS sender for 196 domains — 0.03% of 617,244 SPF-publishing domains. Detection method: include: mechanisms in the SPF record.
Esker is a cloud-based email delivery and document automation platform that provides businesses with outsourced email transmission services. The platform handles the dispatch of transactional and marketing messages through Esker's infrastructure on behalf of customer domains.
In public DNS records, Esker appears predominantly in the SPF configurations of smaller and mid-market businesses within the .com namespace, often paired with Microsoft 365 deployments. This footprint pattern indicates Esker serves as a relay vendor for organisations integrating document workflows with cloud productivity platforms. For email senders and receivers, this means Esker is a trusted component of email authentication infrastructure for SMBs; senders routing mail through Esker depend on maintaining accurate SPF records to preserve delivery reliability.
| Tranco rank band | Domains | Share of its base |
|---|---|---|
| Top 1,000 | 0 | 0.0% |
| Top 10,000 | 5 | 2.6% |
| Top 100,000 | 21 | 10.7% |
| Top 1,000,000 | 157 | 80.1% |
| Unranked | 13 | 6.6% |
| TLD | Domains | Share | |
|---|---|---|---|
| .com | 124 | 63.3% | |
| .fr | 44 | 22.4% | |
| .com.au | 5 | 2.6% | |
| .co.nz | 4 | 2.0% | |
| .be | 3 | 1.5% | |
| .co.uk | 2 | 1.0% | |
| .eu | 2 | 1.0% | |
| .ca | 2 | 1.0% | |
| .org | 2 | 1.0% | |
| .pt | 1 | 0.5% |
Cross-tabulated from the same daily snapshot — the other email services seen on the same 196 domains.
| Type | Service | Domains | Share of Esker users |
|---|---|---|---|
| Mailbox | Microsoft 365 | 100 | 51.0% |
| Mailbox | Proofpoint | 27 | 13.8% |
| Mailbox | Mimecast | 19 | 9.7% |
| Mailbox | Unknown / Other | 15 | 7.7% |
| Mailbox | Google Workspace | 9 | 4.6% |
| Mailbox | Self-Hosted | 6 | 3.1% |
When Esker appears in a domain's SPF record as an authorised sending mechanism, mail transmitted through Esker's infrastructure carries an explicit authentication statement. Esker typically publishes SPF mechanisms (such as dedicated include mechanisms) that establish a clear chain of trust: the domain authorises Esker, Esker publishes its sending infrastructure identifiers, and receiving mail servers can verify alignment between the sender's domain and the SPF-approved source. This creates a responsibility for domain administrators — misconfigured or outdated Esker SPF includes can cause legitimate mail to fail authentication, particularly if an organisation transitions to or away from Esker without updating its SPF record.
See the full Esker data page (KPI cards, trend, sample domains) →
Only if your organisation actually uses Esker to send email—either directly or through a cloud platform integration. If you do use Esker, including it in your SPF is necessary for authentication; if you don't, adding it would incorrectly authorise a third-party sender and weaken your authentication policy.
196 domains in the Tranco top-1M use Esker as their SaaS sender as of July 12, 2026 (0.03% of SPF-publishing domains), according to Live Direct Marketing's daily DNS scan.
Esker accounts for 0.03% 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.
Esker's largest TLD is .com (63.3% of its domains); it appears across 17 TLDs in total.