According to Live Direct Marketing's daily Tranco top-1M scan (July 13, 2026), Mailkit is the email service provider (ESP) for 193 domains — 0.03% of 617,702 SPF-publishing domains. Detection method: include: mechanisms in the SPF record.
Mailkit is an email service provider (ESP) that serves primarily smaller organisations and sites, particularly within the Czech Republic and surrounding regions. It operates as a mail-sending platform commonly integrated into customer environments alongside other providers such as Microsoft 365.
Mailkit's presence in SPF records across the web indicates its role in hybrid mail stacks, where organisations combine multiple email services. For senders, its inclusion in an SPF chain—especially when paired with larger platforms—underscores the importance of careful record maintenance and SPF record length management. Recipients may encounter mail from Mailkit-hosted sources more commonly if they interact with Czech-based or Central European organisations.
| Tranco rank band | Domains | Share of its base |
|---|---|---|
| Top 1,000 | 0 | 0.0% |
| Top 10,000 | 2 | 1.0% |
| Top 100,000 | 31 | 16.1% |
| Top 1,000,000 | 141 | 73.1% |
| Unranked | 19 | 9.8% |
| TLD | Domains | Share | |
|---|---|---|---|
| .cz | 96 | 49.7% | |
| .sk | 23 | 11.9% | |
| .com | 10 | 5.2% | |
| .hr | 6 | 3.1% | |
| .ro | 6 | 3.1% | |
| .es | 4 | 2.1% | |
| .pl | 4 | 2.1% | |
| .hu | 4 | 2.1% | |
| .de | 4 | 2.1% | |
| .it | 3 | 1.6% |
Cross-tabulated from the same daily snapshot — the other email services seen on the same 193 domains.
| Type | Service | Domains | Share of Mailkit users |
|---|---|---|---|
| Mailbox | Microsoft 365 | 62 | 32.1% |
| Mailbox | Google Workspace | 36 | 18.7% |
| Mailbox | Unknown / Other | 21 | 10.9% |
| Mailbox | Self-Hosted | 17 | 8.8% |
| Mailbox | Websupport (SK) | 11 | 5.7% |
| Mailbox | FORPSI (Internet CZ) | 10 | 5.2% |
| ESP | Heureka Mailing (CZ) | 17 | 8.8% |
| ESP | Mailchimp | 12 | 6.2% |
| ESP | Amazon SES | 10 | 5.2% |
| ESP | Zendesk | 7 | 3.6% |
When organisations use Mailkit alongside Microsoft 365 or other major providers, SPF records can quickly accumulate multiple include mechanisms. Each additional ESP raises the DNS query count and increases the risk of exceeding the practical SPF lookup limit (ten DNS queries). Keeping SPF records tightly scoped and removing unused or deprecated includes is especially critical for sites that have added Mailkit to an existing mail infrastructure without decommissioning earlier providers.
See the full Mailkit data page (KPI cards, trend, sample domains) →
Mailkit is a regional email service provider used predominantly by smaller organisations in Central Europe, particularly in the Czech Republic. If your recipient list or sending infrastructure involves Central European audiences or you are evaluating mail providers in that region, it is worth including in your SPF and DMARC validation checks.
193 domains in the Tranco top-1M use Mailkit as their email service provider (ESP) as of July 13, 2026 (0.03% of SPF-publishing domains), according to Live Direct Marketing's daily DNS scan.
Mailkit 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.
Mailkit's largest TLD is .cz (49.7% of its domains); it appears across 33 TLDs in total.