Mailbox provider · Proton Mail
How to verify a Proton Mail address
Can you verify a Proton Mail address?
Yes. A mailbox check asks Proton Mail's mail server whether the @protonmail.com mailbox exists and disconnects before any email is sent. Proton Mail rejected a made-up address in our 23 October 2026 test, so a missing mailbox comes back invalid and a real one valid. Temporary replies and timeouts stay risky until checked again.
Tuned for proton.me, protonmail.com and pm.me addresses and company domains whose MX points at Proton. Five checks a minute, no account needed. Nothing is sent to the address — we ask its mail server whether the mailbox exists, then disconnect.
Paste your @protonmail.com addresses (a mixed list is fine) and check them together.
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Proton Mail verification facts
| Primary mail server (MX) | mail.protonmail.ch (run by Proton) |
|---|---|
| Made-up address, 23 October 2026 | invalid in both rounds, about 10.5 hours apart ("Mailbox not found") |
| Mailbox probe | Yes: asked at the SMTP RCPT TO step, then we disconnect before any message is sent. |
| Catch-all behaviour | Not catch-all: a made-up address was rejected, so a rejection means the mailbox is missing. |
| Typical results | Valid ("Mailbox exists") or invalid ("Mailbox not found"). Risky ("Server would not confirm") when the server gives a temporary reply or times out. |
| Always checked | Syntax, the domain's mail servers (MX), disposable domains, role inboxes (info@, sales@) and likely typos. |
| A list of addresses | Paste or drop it above: the first 100 checks are free with a Google sign-in, no card, results as a CSV. |
| Single-address tool | Proton Mail checker |
From our checker's code and our own dated measurements. Anything we cannot confirm is reported as risky, never valid. Last updated .
How do I check if a @protonmail.com address exists? Paste the address into a mailbox checker such as SimpleVerifier's: it asks Proton Mail's mail server about the mailbox at the SMTP RCPT TO step and disconnects before any email is sent. Proton Mail rejected a made-up @protonmail.com address on 23 October 2026, so a missing mailbox comes back invalid and a real one valid; anything the server won't confirm comes back risky.
Can you verify @protonmail.com addresses?
YesYes. @protonmail.com answers mailbox checks one address at a time.
The checker opens an SMTP conversation with protonmail.com's mail server, offers a random address first to rule out a catch-all, then names your address at RCPT TO and disconnects without sending. A rejection comes back invalid ("Mailbox not found") and an acceptance valid ("Mailbox exists"). Temporary replies come back risky. It always checks the syntax, the domain's MX records, disposable domains and role addresses such as info@ first.
Mailbox existsMailbox not foundServer would not confirmWhat we can and cannot confirm at @protonmail.com
We can confirm
- The address is written correctly (syntax), and the domain publishes working mail servers (MX).
- Whether it is a disposable or role address (info@, sales@) or a likely typo of a bigger domain.
- Whether the @protonmail.com mailbox exists: Proton Mail answers at RCPT TO, so a rejection is invalid ("Mailbox not found") and an acceptance is valid.
We cannot confirm
- A temporary reply or timeout from Proton Mail. Those come back risky ("Server would not confirm") and are worth checking again later.
- That a valid mailbox will stay valid. Old consumer addresses go stale, so re-check before a big send.
- Whether a person reads the inbox, wants your email or agreed to receive it. No checker can see that.
Anything we cannot confirm comes back risky, never valid.
What we measured at protonmail.com
Measured by SimpleVerifier on 23 October 2026 through our production checker and public DNS. No message was sent and no real person's address was used.
| Made-up address, checked twice ~10.5 hours apart | invalid both times ("Mailbox not found") |
|---|---|
| Primary mail server (MX) | mail.protonmail.ch |
| Mail host | Proton |
| DMARC policy | p=quarantine |
| SPF | published, ends ~all |
| MTA-STS | published |
| DNSSEC | signed (DS record) |
Sources: How 51 mailbox providers answer verification checks, SPF, DMARC, MTA-STS and DNSSEC at 51 mailbox providers, both with CSVs (CC BY 4.0). All datasets: research.
Where your @protonmail.com addresses live
Already paying another verifier?
Proton Mail addresses verify cleanly. When we gave Proton's server a made-up protonmail.com address on 7 October 2026, it replied 550 5.1.1 Recipient address rejected: Address does not exist at RCPT TO. Proton uses four domains on the same servers and supports plus aliases, so normalise before you de-duplicate.
Price: this tool is free. Checking a whole email list is from $9/mo, and the first 100 checks are free with Google, no card. See pricing
Live DNS snapshot: protonmail.com
Checked 6 November 2026, 11:13 UTCRead from DNS at the time shown and refreshed at most once a day. MX says where mail for protonmail.com goes; SPF and DMARC describe mail sent from it, not whether any one address exists.
- 5
mail.protonmail.chProton Mail - 10
mailsec.protonmail.chProton Mail
First MX host belongs to Proton Mail.
v=spf1 include:_spf.protonmail.ch ~allp=quarantine: meets the requirement and enforces it. No rua= address, so you get no aggregate reports.
v=DMARC1; p=quarantine; fo=1; aspf=s; adkim=s;Look up any other domain with the MX lookup or the email provider lookup.
Proton Mail at a glance
| Operated by | Proton AG, Geneva, SwitzerlandSource: Proton terms of service |
|---|---|
| Same mailbox system | proton.me (the default for new accounts), protonmail.com, pm.me (paid plans) and protonmail.ch (the original domain) all use mail.protonmail.ch and mailsec.protonmail.chSource: Proton: addresses and aliases |
| MX hosts | mail.protonmail.ch, then mailsec.protonmail.chObserved 7 October 2026 (dig MX) |
| Answer to a made-up address | 550 5.1.1 Recipient address rejected: Address does not exist at RCPT TOObserved 7 October 2026 (SMTP probe of a made-up recipient, no message sent) |
| Address rule | Plus aliases: [email protected] delivers to [email protected]Source: Proton: addresses and aliases |
| Address rule | A pm.me address becomes receive-only if its owner downgrades to the free planSource: Proton: pm.me addresses |
| Inactive accounts | Free accounts must sign in at least once a year or are deleted, after reminders at 30, 15 and 7 days. Paid plans are exemptSource: Proton: inactive accounts |
What a Proton reply tells you
Proton's inbound server gives a specific, standard answer. 550 5.1.1 is the addressing class from RFC 3463, the same family Gmail uses, so a verifier can treat it as a clear invalid with no special handling; see 550 5.1.1. A 250 means Proton will take mail for that address today.
Proton judged the recipient on its merits: our live checker's made-up address was rejected as not found on 7 October 2026. That makes Proton one of the more predictable providers to check. The usual caveats still apply: a 250 confirms the mailbox exists today, not that anyone reads it, and a 4xx reply means retry later rather than invalid.
Four domains, one account
Proton's addresses and aliases page lists the domains it hands out. proton.me is the default for new accounts, protonmail.com can be chosen at signup, pm.me is a short domain for paid plans, and protonmail.ch is the original domain from before 2016. On 7 October 2026 all four published the same protonmail.ch MX hosts.
A paid user can have [email protected] and [email protected] on one account, so the same person may sign up twice with different domains. Proton also supports plus aliases, which means [email protected] reaches [email protected]. Strip the plus tag when de-duplicating, but do not assume two Proton domains with the same username are the same person unless your own data says so.
Free Proton accounts expire after a year unused
Proton deletes free accounts that go a year without a sign-in, and says it warns the owner 30, 15 and 7 days before. Paid accounts are not affected. A Proton address that verified a year ago may be gone now, so re-check older lists; how often to re-verify covers the timing. If a pm.me owner drops to the free plan, Proton turns that address receive-only, so it will still accept your mail even though the owner can no longer send from it.
Common questions
- How do I check if a @protonmail.com address exists?
- Paste the address into a mailbox checker such as SimpleVerifier's: it asks Proton Mail's mail server about the mailbox at the SMTP RCPT TO step and disconnects before any email is sent. Proton Mail rejected a made-up @protonmail.com address on 23 October 2026, so a missing mailbox comes back invalid and a real one valid; anything the server won't confirm comes back risky.
- Can I check a list of Proton Mail addresses for free?
- Yes. Paste the list or drop a CSV on this page and sign in with Google: the first 100 addresses are checked free, no card, once per account, and the results download as a CSV. Single addresses can be checked on this page without an account, five a minute.
- Does checking a Proton Mail address send them an email?
- No. The checker opens a connection to the mail server, asks about the mailbox at the RCPT TO step and disconnects before any message is sent. The owner of the address is not notified.
- Why does my Proton Mail address come back risky?
- Usually because the check was cut short: Proton Mail's server gave a temporary reply or timed out, or today's free-tool capacity ran out. Proton Mail normally answers clearly, so check it again later before you drop it.
- Can you check if a Proton Mail address exists?
- Yes. Proton's mail server rejects unknown recipients at the RCPT TO step. On 7 October 2026 it answered a made-up protonmail.com address with '550 5.1.1 Recipient address rejected: Address does not exist', so a mailbox check gives a clear answer.
- Are proton.me and protonmail.com the same service?
- Yes. Proton lists proton.me, protonmail.com, pm.me and protonmail.ch as its address domains, and all four use the same mail.protonmail.ch servers. proton.me is the default for new accounts.
- Does Proton Mail support plus addressing?
- Yes. Proton's support pages describe plus aliases: adding a plus sign and a word after the username creates a variation that delivers to the same inbox.
- Do inactive Proton accounts get deleted?
- Free accounts do. Proton says a free account must be signed in to at least once a year to avoid deletion, and its inactive-account policy does not apply to paid plans.
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