According to Live Direct Marketing's daily Tranco top-1M scan (July 13, 2026), Bullhorn is the email service provider (ESP) for 103 domains — 0.02% of 617,702 SPF-publishing domains. Detection method: include: mechanisms in the SPF record.
Bullhorn is a talent management and customer relationship management platform that incorporates email capabilities for candidate outreach and pipeline communication. The service is provided by Bullhorn Inc., a cloud-based software company serving recruitment agencies, staffing firms, and talent-focused enterprises.
Bullhorn's SPF authentication footprint is concentrated in smaller organisations and the .com domain space, rather than appearing uniformly across enterprise-scale deployments. Its frequent co-occurrence with Microsoft 365 suggests a hybrid mail stack configuration where Bullhorn handles application-specific workflows—candidate notifications, job alerts, or process confirmations—whilst Microsoft 365 serves as the primary email platform. For mail receivers, the relative infrequency of Bullhorn-authenticated messages compared to major providers means they have accumulated less direct reputation history from Bullhorn sources, which can influence filtering approach and authentication signal interpretation.
| Tranco rank band | Domains | Share of its base |
|---|---|---|
| Top 1,000 | 0 | 0.0% |
| Top 10,000 | 0 | 0.0% |
| Top 100,000 | 5 | 4.9% |
| Top 1,000,000 | 81 | 78.6% |
| Unranked | 17 | 16.5% |
| TLD | Domains | Share | |
|---|---|---|---|
| .com | 81 | 78.6% | |
| .co.uk | 6 | 5.8% | |
| .com.au | 2 | 1.9% | |
| .org | 2 | 1.9% | |
| .in | 1 | 1.0% | |
| .it | 1 | 1.0% | |
| .net | 1 | 1.0% | |
| .ie | 1 | 1.0% | |
| .fr | 1 | 1.0% | |
| .nl | 1 | 1.0% |
Cross-tabulated from the same daily snapshot — the other email services seen on the same 103 domains.
| Type | Service | Domains | Share of Bullhorn users |
|---|---|---|---|
| Mailbox | Microsoft 365 | 57 | 55.3% |
| Mailbox | Mimecast | 16 | 15.5% |
| Mailbox | Google Workspace | 12 | 11.7% |
| Mailbox | Proofpoint | 7 | 6.8% |
| Mailbox | Cisco IronPort | 3 | 2.9% |
| Mailbox | Proofpoint Essentials | 2 | 1.9% |
| ESP | HubSpot | 46 | 44.7% |
| ESP | Salesforce | 26 | 25.2% |
| ESP | SendGrid (Twilio) | 20 | 19.4% |
| ESP | Amazon SES | 15 | 14.6% |
When Bullhorn is deployed alongside Microsoft 365, both providers' SPF mechanisms are typically included in the domain's authentication record. Mail receivers and ISPs accumulate reputation data separately for each authenticated source. Because Bullhorn mail is encountered less frequently than mail from dominant providers due to its concentration in smaller organisations, ISPs may have limited direct reputation history for Bullhorn-authenticated traffic, potentially resulting in less granular filtering rules or signal strength. Organisations using this hybrid configuration should monitor delivery performance and sender reputation across both authentication paths.
See the full Bullhorn data page (KPI cards, trend, sample domains) →
Bullhorn is a talent management platform with integrated email capabilities used by recruitment and staffing organisations for candidate communication and workflow-triggered mail. Its SPF include is added when you use Bullhorn's outreach features; since Bullhorn is primarily deployed by smaller organisations, mail receivers typically encounter it less frequently than major email providers.
103 domains in the Tranco top-1M use Bullhorn as their email service provider (ESP) as of July 13, 2026 (0.02% of SPF-publishing domains), according to Live Direct Marketing's daily DNS scan.
Bullhorn 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.
Bullhorn's largest TLD is .com (78.6% of its domains); it appears across 16 TLDs in total.