ProtonMail mailbox provider
According to Live Direct Marketing's daily Tranco top-1M scan (September 13, 2026), ProtonMail is the mailbox provider for 1,730 domains — 0.26% of 664,797 domains with MX records. Detection method: primary MX record (lowest preference).
Key facts
- 1,730 domains in the Tranco top-1M use ProtonMail (0.26% of domains with MX records).
- Snapshot date: 2026-09-13 — recomputed every day.
- Strongest TLD: .com (43.0% of its domains).
- Region skew: Global / US-skewed.
- Most co-used service: Amazon SES.
- Directory category: mailbox provider.
Why ProtonMail appears in this category
Swiss-based end-to-end encrypted mailbox. Popular with privacy-conscious users.
We classify it as a mailbox provider 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.
ProtonMail is an end-to-end encrypted email service operated by Proton AG, a Switzerland-based company. The platform prioritises user privacy and message encryption, appealing to organisations and individuals concerned with email confidentiality and data protection.
Across the web, ProtonMail's presence skews toward smaller sites and organisations rather than the largest consumer or enterprise brands. The service appears frequently alongside Mailgun, suggesting adoption among smaller businesses and privacy-conscious operations. This distribution means email senders encounter ProtonMail recipients less uniformly than they do users of mainstream providers such as Gmail or Outlook, and the service tends to reach more security-aware audiences.
Where ProtonMail sits in the Tranco ranking
| Tranco rank band | Domains | Share of its base |
|---|---|---|
| Top 1,000 | 0 | 0.0% |
| Top 10,000 | 36 | 2.1% |
| Top 100,000 | 236 | 13.6% |
| Top 1,000,000 | 1,438 | 83.1% |
| Unranked | 20 | 1.2% |
Top-level domain split
| TLD | Domains | Share | |
|---|---|---|---|
| .com | 744 | 43.0% | |
| .org | 146 | 8.4% | |
| .net | 125 | 7.2% | |
| .io | 76 | 4.4% | |
| .dev | 31 | 1.8% | |
| .de | 25 | 1.4% | |
| .fr | 21 | 1.2% | |
| .me | 20 | 1.2% | |
| .gg | 20 | 1.2% | |
| .cc | 20 | 1.2% |
What ProtonMail users also use
Cross-tabulated from the same daily snapshot — the other email services seen on the same 1,730 domains.
| Type | Service | Domains | Share of ProtonMail users |
|---|---|---|---|
| ESP | Amazon SES | 61 | 3.5% |
| ESP | Mailgun | 59 | 3.4% |
| ESP | SendGrid (Twilio) | 33 | 1.9% |
| ESP | Mailjet (Sinch) | 32 | 1.8% |
| ESP | MailerLite | 25 | 1.4% |
| ESP | Brevo (ex-Sendinblue) | 25 | 1.4% |
| ESP | Zendesk | 20 | 1.2% |
| ESP | MailerSend | 16 | 0.9% |
| ESP | Mailchimp | 16 | 0.9% |
| ESP | Mandrill | 14 | 0.8% |
Representing smaller, privacy-conscious recipient audiences
ProtonMail's user base—concentrated among privacy-focused individuals and smaller organisations—represents a distinct audience segment within email. These users typically prioritise authentication security and compliance, meaning properly validated mail is particularly important for reaching them reliably. Testing deliverability against ProtonMail is therefore valuable when your recipient strategy includes privacy-conscious segments, though the service does not represent mainstream consumer or enterprise email patterns.
See the full ProtonMail data page (KPI cards, trend, sample domains) →
Run a free inbox-placement test across Gmail, Outlook, Yahoo and more — see exactly where your mail lands and why.
Frequently asked questions
Should I test email deliverability against ProtonMail?
ProtonMail is worth testing because it serves privacy-conscious users who typically enforce stricter authentication standards. However, as it represents a smaller portion of typical recipient bases than Gmail or Outlook, include it as part of a comprehensive strategy rather than your primary focus.
How many domains use ProtonMail?
1,730 domains in the Tranco top-1M use ProtonMail as their mailbox provider as of September 13, 2026 (0.26% of domains with MX records), according to Live Direct Marketing's daily DNS scan.
Is ProtonMail common enough to affect email deliverability testing?
ProtonMail accounts for 0.26% 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 ProtonMail most?
ProtonMail's largest TLD is .com (43.0% of its domains); it appears across 187 TLDs in total.