Proton Mail email checker: what can and can't be confirmed
This Proton Mail checker tests a proton.me, protonmail.com or pm.me address, or one on a company domain hosted at Proton, for syntax, a working mail server and disposable use, then asks Proton's server about the mailbox. Proton doesn't publish how it answers that question, and custom domains can catch all mail, so many Proton results are risky, not valid. Nothing is sent.
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.
Sample result
name@proton.me passes the checks that can run, but Proton didn't confirm it.
- name@proton.me
- Reason
- Server would not confirm
- Mail host (MX)
- Proton Mail
What this means for you
Risky means unconfirmed, not bad; a confirmed signup is a reasonable send.
- Catches broken syntax and dead domains
- Flags disposable and role addresses
- Spots custom domains hosted at Proton
- Says when Proton won't confirm
- Proton Mail
- proton.me
- pm.me
By SimpleVerifier Team · Last updated
How do I check a Proton Mail address?
- Enter one address, such as
name@proton.meorjane@acme.exampleon a domain hosted at Proton. - Press Check. Syntax, domain and disposable checks run, and the Mail host line shows Proton Mail when the domain's MX points at Proton.
- The checker asks about a made-up address first, then the real one, and disconnects.
- Read risky as unconfirmed. Valid appears only when Proton accepted the address and rejected the made-up one; invalid only when it rejected the address or the domain fails.
Example
- You enter
- An illustrative address:
name@proton.me. - You get
- Syntax, domain and disposable results plus Proton's answer to the mailbox check, with Mail host "Proton Mail". Risky is common: Proton doesn't publish how it answers, and custom domains with a catch-all come back "Accepts all addresses". Never upgraded to valid without a clear accept and a rejected made-up address.
- Limits
- Five checks a minute per IP address, one address at a time, no account needed.
Can you verify a Proton Mail address?
Only partly, and this page says so up front. Proton's mail servers (MX mail.protonmail.ch and mailsec.protonmail.ch) are asked the same RCPT TO question as any other provider, but Proton publishes no reference for what they answer. Proton's own help says that without a catch-all, a message to a wrong address gets "a bounce-back message"; it doesn't say whether that refusal comes during the conversation, where a check can see it, or afterwards as a separate bounce, where it can't.
So the checker reports exactly what Proton's server said, tests a made-up address first, and never turns an unclear answer into valid. Expect risky often. What it reliably catches is the rest: broken syntax, a domain with no mail server, throwaway domains and role addresses.
Why do Proton custom domains often come back risky?
Because of catch-all addresses. On any paid plan, Proton lets a custom domain set a catch-all address that receives mail sent to any address at the domain that doesn't exist. With it on, the checker's made-up address is accepted, and the result is risky with "Accepts all addresses".
Privacy-minded people also hand out aliases and forwarding addresses that change over time, so a Proton address on an old list deserves the same caution as any unconfirmed one: send in a small batch first and suppress hard bounces.
Should I send to a Proton address that comes back risky?
Decide by where it came from. A Proton address typed into your own signup form, ideally confirmed by double opt-in, is a reasonable send; risky only means Proton didn't confirm it. One from a purchased or scraped list is a bigger risk, as it is at any provider.
For a whole list, the email list cleaner removes duplicates, bad syntax and dead domains in your browser before any mailbox checks.
Who uses this tool, and for what?
- SaaS and newsletter signups
- Catch a broken or disposable address at signup, and understand why a real Proton user comes back risky rather than valid.
- B2B prospectors
- Spot companies that host their domain at Proton and see at once whether the domain catches all mail.
- List owners
- Plan a cautious first send for Proton addresses instead of dropping them because they weren't confirmed.
What can’t this tool tell you?
- It often can't confirm that a Proton mailbox exists; those results are risky.
- Custom domains with a catch-all address come back risky as catch-all.
- Proton doesn't publish its server's replies to a mailbox check, so this page makes no claim beyond what the server said.
- One address at a time, five a minute.
Common questions
- Why does my Proton Mail address show as risky?
- Proton doesn't publish how its servers answer a mailbox check, and custom domains can catch all mail. When Proton accepts a made-up address or gives no clear answer, the checker reports risky rather than guessing valid.
- Can it still tell me a Proton address is invalid?
- Yes, when the problem is something that can be checked: broken syntax, a domain with no mail server, a disposable domain, or Proton rejecting the address outright during the check.
- Are proton.me, protonmail.com and pm.me the same service?
- Yes. They are Proton Mail domains served by the same mail hosts (MX mail.protonmail.ch). Company domains hosted at Proton use the same hosts, which is how the checker spots them.
- Is a proton.me address a business email?
- No. Anyone can open one, so it counts as personal webmail. A company domain hosted at Proton is a work address.
- Does the person get notified?
- No. The checker disconnects after the RCPT TO step, before any message is sent.
- Is this Proton checker free?
- Yes, five checks a minute with no account. For a list, sign in with Google for 100 free email checks, no card.
Sources
That was one address. Most people have a list.
The free checker does five addresses a minute, one at a time — fine for spot-checking, useless for a CSV of 40,000.
- Upload a CSV up to 100,000 rows
- Valid, risky and invalid exported as separate files
- Repeat checks free for 14 days, no new connections
One plan, cancel anytime, no contract. Sign in with Google and your first 100 email checks are free, no card. The free tools stay free either way.