Zoner (CZ) mailbox provider
According to Live Direct Marketing's daily Tranco top-1M scan (September 19, 2026), Zoner (CZ) is the mailbox provider for 148 domains — 0.02% of 680,914 domains with MX records. Detection method: primary MX record (lowest preference).
Key facts
- 148 domains in the Tranco top-1M use Zoner (CZ) (0.02% of domains with MX records).
- Snapshot date: 2026-09-19 — recomputed every day.
- Strongest TLD: .cz (48.0% of its domains).
- Region skew: Czechia.
- Most co-used service: Heureka Mailing (CZ).
- Directory category: hosting mail bundle.
Why Zoner (CZ) appears in this category
Long-running CZ/SK hosting brand.
We classify it as a hosting mail bundle from primary MX record (lowest preference) matching a maintained provider rule. This is infrastructure attribution from public DNS, not evidence of a direct contract or exclusive use.
Zoner is a Czech-based regional email service provider serving mailboxes primarily within Czechia. It operates as a smaller, locally-focused alternative to global providers, concentrated in the .cz domain ecosystem and oriented toward domestic Czech organisations and businesses.
When Zoner appears as a primary MX record across a website's mail infrastructure, it signals a smaller or regionally-rooted organisation rather than an enterprise with global deployment. For senders targeting Czech audiences, Zoner's presence is worth accounting for when the recipient base skews towards domestic Czech entities; it is frequently observed alongside Heureka Mailing, another Czech-operated mail service, suggesting common patterns in regional Czech infrastructure.
Where Zoner (CZ) sits in the Tranco ranking
| Tranco rank band | Domains | Share of its base |
|---|---|---|
| Top 1,000 | 0 | 0.0% |
| Top 10,000 | 1 | 0.7% |
| Top 100,000 | 9 | 6.1% |
| Top 1,000,000 | 137 | 92.6% |
| Unranked | 1 | 0.7% |
Top-level domain split
| TLD | Domains | Share | |
|---|---|---|---|
| .cz | 71 | 48.0% | |
| .com | 19 | 12.8% | |
| .sk | 17 | 11.5% | |
| .hu | 5 | 3.4% | |
| .pl | 3 | 2.0% | |
| .de | 3 | 2.0% | |
| .eu | 3 | 2.0% | |
| .org | 2 | 1.4% | |
| .be | 2 | 1.4% | |
| .si | 2 | 1.4% |
What Zoner (CZ) users also use
Cross-tabulated from the same daily snapshot — the other email services seen on the same 148 domains.
| Type | Service | Domains | Share of Zoner (CZ) users |
|---|---|---|---|
| ESP | Heureka Mailing (CZ) | 15 | 10.1% |
| ESP | SmartEmailing | 10 | 6.8% |
| ESP | SparkPost | 5 | 3.4% |
| ESP | Mailjet (Sinch) | 3 | 2.0% |
| ESP | Mailkit | 3 | 2.0% |
| ESP | Amazon SES | 3 | 2.0% |
| ESP | Zendesk | 2 | 1.4% |
| ESP | Mailchimp | 2 | 1.4% |
| ESP | Mailgun | 2 | 1.4% |
| ESP | Elastic Email | 2 | 1.4% |
Regional testing relevance for Zoner
Because Zoner's footprint concentrates in the Czech market and the .cz domain space, inbox placement testing against Zoner is most relevant when your sending programme targets Czech recipients or Czech-registered domains. A deliverability assessment that aims to cover European regional providers should include Zoner, particularly for campaigns destined for smaller Czech organisations; however, if your audience is predominantly anglophone or non-Czech, Zoner may fall outside the core test matrix for your programme.
See the full Zoner (CZ) data page (KPI cards, trend, sample domains) →
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Frequently asked questions
Do I need to test emails against Zoner?
If your recipients include Czech-based mailboxes or Czech organisations, Zoner is a relevant test case; otherwise, it is not critical to most international sending programmes.
How many domains use Zoner (CZ)?
148 domains in the Tranco top-1M use Zoner (CZ) as their mailbox provider as of September 19, 2026 (0.02% of domains with MX records), according to Live Direct Marketing's daily DNS scan.
Is Zoner (CZ) common enough to affect email deliverability testing?
Zoner (CZ) accounts for 0.02% of domains with MX records 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 Zoner (CZ) most?
Zoner (CZ)'s largest TLD is .cz (48.0% of its domains); it appears across 28 TLDs in total.