Esker SaaS sender
According to Live Direct Marketing's daily Tranco top-1M scan (September 19, 2026), Esker is the SaaS sender for 209 domains — 0.03% of 642,799 SPF-publishing domains. Detection method: include: mechanisms in the SPF record.
Key facts
- 209 domains in the Tranco top-1M use Esker (0.03% of SPF-publishing domains).
- Snapshot date: 2026-09-19 — recomputed every day.
- Strongest TLD: .com (64.1% of its domains).
- Most co-used service: Microsoft 365.
- Directory category: SaaS sender.
Why Esker appears in this category
Esker — document automation cloud.
We classify it as a SaaS sender from include: mechanisms in the SPF record matching a maintained provider rule. This is infrastructure attribution from public DNS, not evidence of a direct contract or exclusive use.
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.
Where Esker sits in the Tranco ranking
| Tranco rank band | Domains | Share of its base |
|---|---|---|
| Top 1,000 | 0 | 0.0% |
| Top 10,000 | 3 | 1.4% |
| Top 100,000 | 21 | 10.0% |
| Top 1,000,000 | 182 | 87.1% |
| Unranked | 3 | 1.4% |
Top-level domain split
| TLD | Domains | Share | |
|---|---|---|---|
| .com | 134 | 64.1% | |
| .fr | 43 | 20.6% | |
| .co.nz | 6 | 2.9% | |
| .com.au | 5 | 2.4% | |
| .be | 3 | 1.4% | |
| .com.my | 3 | 1.4% | |
| .ca | 2 | 1.0% | |
| .eu | 2 | 1.0% | |
| .co.uk | 2 | 1.0% | |
| .org | 2 | 1.0% |
What Esker users also use
Cross-tabulated from the same daily snapshot — the other email services seen on the same 209 domains.
| Type | Service | Domains | Share of Esker users |
|---|---|---|---|
| Mailbox | Microsoft 365 | 105 | 50.2% |
| Mailbox | Proofpoint | 29 | 13.9% |
| Mailbox | Mimecast | 22 | 10.5% |
| Mailbox | Unknown / Other | 17 | 8.1% |
| Mailbox | Google Workspace | 9 | 4.3% |
| Mailbox | Cisco IronPort | 5 | 2.4% |
SPF mechanisms and sender authentication alignment
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) →
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Frequently asked questions
Should I include Esker in my domain's SPF record?
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.
How many domains use Esker?
209 domains in the Tranco top-1M use Esker as their SaaS sender as of September 19, 2026 (0.03% of SPF-publishing domains), according to Live Direct Marketing's daily DNS scan.
Is Esker common enough to affect email deliverability testing?
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.
Which countries or TLDs use Esker most?
Esker's largest TLD is .com (64.1% of its domains); it appears across 17 TLDs in total.