KnowBe4 SaaS sender
According to Live Direct Marketing's daily Tranco top-1M scan (September 12, 2026), KnowBe4 is the SaaS sender for 3,364 domains — 0.53% of 629,828 SPF-publishing domains. Detection method: include: mechanisms in the SPF record.
Key facts
- 3,364 domains in the Tranco top-1M use KnowBe4 (0.53% of SPF-publishing domains).
- Snapshot date: 2026-09-12 — recomputed every day.
- 30-day share change: -0.02 pp.
- Strongest TLD: .com (55.7% of its domains).
- Most co-used service: Microsoft 365.
- Directory category: SaaS sender.
Why KnowBe4 appears in this category
KnowBe4 — security awareness training and simulated phishing platform, the largest vendor in that category.
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.
KnowBe4 is a security awareness training platform that includes email delivery capabilities for organisations running phishing simulations, policy training, and internal communication campaigns. The platform operates as a delegated sender, transmitting email on behalf of client domains through its own infrastructure.
Across the global domain population, KnowBe4 appears predominantly in the long tail of smaller and mid-market organisations rather than enterprise incumbents, with a concentration in the .com namespace. The service is frequently observed running alongside Microsoft 365 environments, indicating uptake among organisations with a Microsoft-centric security posture. For email senders and receivers, this distribution pattern suggests that KnowBe4 traffic is typically intra-organisational or training-focused rather than external marketing or transactional mail.
Where KnowBe4 sits in the Tranco ranking
| Tranco rank band | Domains | Share of its base |
|---|---|---|
| Top 1,000 | 5 | 0.1% |
| Top 10,000 | 35 | 1.0% |
| Top 100,000 | 445 | 13.2% |
| Top 1,000,000 | 2,865 | 85.2% |
| Unranked | 14 | 0.4% |
Top-level domain split
| TLD | Domains | Share | |
|---|---|---|---|
| .com | 1,873 | 55.7% | |
| .org | 392 | 11.7% | |
| .edu | 145 | 4.3% | |
| .gov | 122 | 3.6% | |
| .ca | 71 | 2.1% | |
| .co.uk | 67 | 2.0% | |
| .de | 57 | 1.7% | |
| .net | 51 | 1.5% | |
| .nl | 36 | 1.1% | |
| .com.au | 33 | 1.0% |
What KnowBe4 users also use
Cross-tabulated from the same daily snapshot — the other email services seen on the same 3,364 domains.
| Type | Service | Domains | Share of KnowBe4 users |
|---|---|---|---|
| Mailbox | Microsoft 365 | 1,875 | 55.7% |
| Mailbox | Google Workspace | 482 | 14.3% |
| Mailbox | Mimecast | 269 | 8.0% |
| Mailbox | Proofpoint | 144 | 4.3% |
| Mailbox | Unknown / Other | 117 | 3.5% |
| Mailbox | Barracuda | 113 | 3.4% |
Delegated sending and sender reputation implications
KnowBe4 operates as a delegated sender by appearing in client domains' SPF records, allowing the service to dispatch mail from those domains. Because the sending infrastructure is distributed across a long tail of smaller organisations rather than consolidated in a few high-volume senders, individual KnowBe4-originated mail lacks the sender reputation weight of mainstream transactional platforms. Email receivers may apply additional scrutiny to mail from domains sending via KnowBe4 if those domains have not independently established strong reputation, and organisations using the platform should monitor their domain's deliverability separately.
See the full KnowBe4 data page (KPI cards, trend, sample domains) →
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Frequently asked questions
What is KnowBe4 and why might I see it sending email from a domain?
KnowBe4 is a security awareness platform that sends email on behalf of organisations running internal training campaigns, typically phishing simulations or policy reminders. You may receive KnowBe4-delivered mail if your organisation uses the platform, or occasionally from external senders who use it for employee awareness training.
How many domains use KnowBe4?
3,364 domains in the Tranco top-1M use KnowBe4 as their SaaS sender as of September 12, 2026 (0.53% of SPF-publishing domains), according to Live Direct Marketing's daily DNS scan.
Is KnowBe4 common enough to affect email deliverability testing?
KnowBe4 accounts for 0.53% 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.
Is KnowBe4 growing or declining?
KnowBe4 is declining — its share moved -0.02 pp over the last 30 days (as of September 12, 2026).
Which countries or TLDs use KnowBe4 most?
KnowBe4's largest TLD is .com (55.7% of its domains); it appears across 151 TLDs in total.