According to Live Direct Marketing's daily Tranco top-1M scan (July 13, 2026), Cal.com is the SaaS sender for 95 domains — 0.02% of 617,702 SPF-publishing domains. Detection method: include: mechanisms in the SPF record.
Cal.com is a scheduling and calendar SaaS platform that enables its customers to send email on behalf of their own domains—allowing users to outsource calendar synchronisation, booking links, and scheduling notifications without owning the underlying mail infrastructure. The platform is operated by Cal.com and maintained as a commercial service.
Cal.com's SPF footprint appears predominantly in smaller and mid-market deployments rather than enterprise-scale operations, concentrated primarily in the .com domain space. This visibility pattern matters for email deliverability professionals: if you're monitoring or filtering on behalf of a domain, you may encounter Cal.com's sending infrastructure; if you're protecting recipients, you should understand that Cal.com sits alongside common enterprise providers like Microsoft 365 in many deployment stacks, and its SPF inclusion indicates a scheduling tool is handling calendar-related outbound mail.
| Tranco rank band | Domains | Share of its base |
|---|---|---|
| Top 1,000 | 1 | 1.1% |
| Top 10,000 | 5 | 5.3% |
| Top 100,000 | 10 | 10.5% |
| Top 1,000,000 | 67 | 70.5% |
| Unranked | 12 | 12.6% |
| TLD | Domains | Share | |
|---|---|---|---|
| .com | 70 | 73.7% | |
| .org | 5 | 5.3% | |
| .com.br | 3 | 3.2% | |
| .com.ar | 2 | 2.1% | |
| .de | 2 | 2.1% | |
| .es | 1 | 1.1% | |
| .br | 1 | 1.1% | |
| .be | 1 | 1.1% | |
| .nl | 1 | 1.1% | |
| .edu | 1 | 1.1% |
Cross-tabulated from the same daily snapshot — the other email services seen on the same 95 domains.
| Type | Service | Domains | Share of Cal.com users |
|---|---|---|---|
| Mailbox | Microsoft 365 | 41 | 43.2% |
| Mailbox | Google Workspace | 17 | 17.9% |
| Mailbox | Self-Hosted | 8 | 8.4% |
| Mailbox | Unknown / Other | 6 | 6.3% |
| Mailbox | Generic / unmatched (mx*.*) | 5 | 5.3% |
| Mailbox | Proofpoint | 5 | 5.3% |
When Cal.com is deployed alongside Microsoft 365 or other mail service providers, domains must manage multiple SPF include statements within a constrained record structure. This multi-provider stacking increases the complexity of SPF authentication and can contribute to DNS lookup exhaustion when too many authorised senders are chained together. Deliverability professionals should audit SPF records containing Cal.com and other third-party mail authorisations to confirm they do not create maintenance bottlenecks, and to verify that all authorised senders are correctly ordered and necessary.
See the full Cal.com data page (KPI cards, trend, sample domains) →
Cal.com is a calendar and scheduling SaaS platform that sends email notifications on behalf of your domain—such as booking confirmations and meeting reminders. It appears in your SPF record because you have authorised it to send calendar-related mail.
95 domains in the Tranco top-1M use Cal.com as their SaaS sender as of July 13, 2026 (0.02% of SPF-publishing domains), according to Live Direct Marketing's daily DNS scan.
Cal.com 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.
Cal.com's largest TLD is .com (73.7% of its domains); it appears across 18 TLDs in total.