In short. “Anonymous email” means different things: temporary inboxes, services that send mail without a signature, mailboxes that need no phone number. Each hides one thing, and none hides everything. A message cannot be delivered without addresses, and a name is not the only thing that gives a person away. Below: what really identifies you in email, what real cases show, and how to lower the risk.
What people call anonymous email
- Temporary inboxes. An address for a few minutes or hours, no sign-up. Handy for one-off subscriptions. Some of these inboxes are public: anyone who knows the address can read the mail in it.
- Anonymous sending services. A form on a website sends a message from someone else’s address. You usually cannot reply to such a message, and the service itself sees who sent what.
- Mailboxes that ask for no personal data. Regular email that does not need a phone number or another email address to sign up.
- Aliases. Extra addresses that forward mail to your main inbox and keep it hidden from websites.
What actually gives you away
IP address
An email provider sees your IP address every time you sign in or send a message. Some providers also put the sender’s IP into the message’s technical headers, where the recipient can see it [1]. Tor helps hide your IP even from the email provider [2].
Payment
A bank card is tied to a name, and the payment provider keeps records of the payment. A cryptocurrency payment is visible on a public blockchain [3].
Recovery address and phone number
Account recovery ties a mailbox to another account or number. If that account is in your name, the mailbox is only as anonymous as that.
Metadata
Even with end-to-end encryption, who writes to whom and when stays visible: mail cannot be delivered without addresses. More in What is end-to-end encryption?
Content and style
Your signature, pet phrases, the time zone in the headers, hidden data in attachments: location in photos, the author’s name in documents.
What real cases show
In publicly known cases, the authorities did not break email encryption. What they got was what sat next to it:
- An IP address recorded on order. In 2021, Proton was ordered by Swiss authorities to start recording the IP address of one account and handed it over. It could not hand over message content [4, 5].
- A recovery address. In 2024, Proton handed over a user’s recovery address in response to a request from Spanish police, passed on through Swiss authorities. It was an iCloud address, and Apple used it to identify the person [6].
- Payment data. In 2026, payment data for a mailbox, passed on by Proton through Swiss authorities, was used to identify the user [7].
- Future mail. In 2020, a court in Cologne ordered Tutanota to keep future unencrypted mail for one mailbox. Encrypted mail already stored was not affected [8].
How to lower the risk
- Don’t use a mailbox in your name as the recovery address, and don’t link a phone number if you can avoid it.
- If hiding your IP address matters, sign in to your email over Tor [2]. More: what Tor hides and what it doesn’t.
- Remember that paying by card ties the mailbox to your name.
- Use different addresses for different purposes: aliases keep your main address out of sight.
- Strip hidden data from attachments before you send them.
- Remember that metadata is always visible.
Why we don’t use the term
We don’t call Methmail anonymous email: promising anonymity in email would not be honest. Instead of promises, we publish an inventory: what we will keep, what we will see but not keep, what others will get, and what we can be ordered to do. The first rows are already on the Privacy page.
This applies to us too: a court in the country where our servers will be, or where members of our team live, will be able to order us to start recording the IP addresses of a specific account, to keep its future incoming mail from other providers before it is encrypted, or to copy its future mail to other providers sent without PGP. What we could and could not hand over is in the inventory.
Sources
- Privacy Guides: Email Services, Criteria section (updated June 28, 2026). https://www.privacyguides.org/en/email/#criteria
- EFF, Surveillance Self-Defense: How to Use Tor. https://ssd.eff.org/module/how-to-use-tor
- Bitcoin.org: Protect your privacy. https://bitcoin.org/en/protect-your-privacy
- Proton blog, September 6, 2021. https://proton.me/blog/climate-activist-arrest
- TechCrunch, September 6, 2021: “ProtonMail logged IP address of French activist after order by Swiss authorities”. https://techcrunch.com/2021/09/06/protonmail-logged-ip-address-of-french-activist-after-order-by-swiss-authorities/
- TechSpot, May 13, 2024. https://www.techspot.com/news/102981-proton-mail-provided-user-data-led-arrest-spain.html
- 404 Media, March 5, 2026. https://www.404media.co/proton-mail-helped-fbi-unmask-anonymous-stop-cop-city-protestor/
- The Register, December 8, 2020. https://www.theregister.com/2020/12/08/tutanota_backdoor_court_order/