How to use a free number to verify ProtonMail
The process takes under two minutes and requires nothing except a browser. Open asms.ai and browse the list of available public numbers. Each listing shows the country of origin and a preview of recent incoming messages, which tells you the number is live and actively receiving SMS.
Choose a number from whichever country you prefer. The United States, United Kingdom, Germany, Georgia, and Ukraine are all available, with new countries added as fresh stock is sourced. Copy the number and paste it into the ProtonMail sign-up form where it asks for phone verification.
ProtonMail sends a one-time passcode to that number by SMS. Return to the asms.ai inbox page for that number. The page refreshes automatically every few seconds. The OTP code typically arrives within 30 to 60 seconds. Copy it, paste it back into ProtonMail, and verification is complete.
You have not created an account on asms.ai, provided your email address, or left any identifying information behind.
Is it really free? How asms.ai funds itself
The public shared numbers on asms.ai are permanently free. There is no trial period, no expiry date, and no advertising on the inbox page.
The business model is straightforward: asms.ai is funded by users who pay for a private number or for programmatic API access. Developers building automated workflows use the REST API or the native MCP server to receive SMS programmatically in AI agent pipelines. Those subscriptions keep the free public tier running at no cost to casual users.
Formerly known as AnonymSMS, asms.ai has operated continuously since 2018. The free public number list has been available throughout that period without any hidden catch.
Why people use a temporary number for ProtonMail
ProtonMail is a privacy-first email service, so handing Proton your real phone number during sign-up creates a link between your personal mobile and your private inbox. That association sits in account records indefinitely. If you later lose access to that phone number, want to separate your identity from the account, or if Proton ever experiences a data incident, your real contact detail is attached to what was meant to be an anonymous inbox.
There are also common operational reasons. Journalists, researchers, security professionals, and privacy-conscious users routinely create secondary ProtonMail accounts for specific projects or compartmentalised correspondence. Using a personal number on those accounts directly undermines the operational separation they need.
Then there are simpler cases: someone evaluating ProtonMail before committing to it, a developer creating a test account, or a user who simply objects to mandatory phone fields on principle. A free temporary phone number for ProtonMail verification handles all of these without requiring a second SIM or a monthly subscription to a virtual number service.
Will ProtonMail accept a shared number?
ProtonMail accepts standard SMS delivery from most countries and does not blanket-block VoIP or shared services. In practice the majority of numbers on asms.ai receive ProtonMail verification codes without any difficulty.
The honest caveat: shared numbers are, by definition, public. A number that has been used by thousands of people across many different platforms can appear on spam or abuse databases that some services query before accepting a number. ProtonMail may occasionally decline to deliver a code to a heavily used shared number.
If a code does not arrive within two minutes, do not keep retrying on the same number. That is a sign the number has been flagged for that platform or is experiencing high traffic. Instead, pick a different number from a different country and start fresh. The asms.ai list is refreshed daily, so there is nearly always a clean option available.
Opening two or three candidate numbers in separate tabs before you start the ProtonMail sign-up form is the most practical approach. If the first number stalls, you can switch without restarting the entire registration flow.
Privacy and security considerations
Because asms.ai public inboxes are shared, any message that arrives is visible to anyone who visits that page. The service is built for one-time verification codes, not private correspondence, and that distinction matters.
Use the code as soon as it appears. The code is valid only for a short window and tied to a single verification session, but acting quickly reduces any theoretical exposure.
On the asms.ai side, the service does not require visitors to log in, does not set identifying cookies, and does not record which user retrieved which code. Your interaction with the inbox is not associated with any persistent identity.
After ProtonMail verification is complete, the shared number is not actively connected to your account. If ProtonMail asks for re-verification in future because of a login from an unusual location or a password reset, you can return to asms.ai and use the same number again if it is still listed, or choose a different one. If inbox privacy is critical, for example when verifying accounts for business use or handling sensitive correspondence, the private number tier gives you an inbox only you can access.
Other platforms you can verify with a free number
The same workflow that covers ProtonMail verification works for a wide range of other services. asms.ai public numbers receive SMS from social networks, messaging apps, developer platforms, marketplace services, and other email providers. If a service delivers an OTP by text, a shared number can generally receive it.
Common use cases include creating secondary accounts on platforms that require phone verification, testing sign-up flows during product development, registering on services not yet available in your country, and bypassing mandatory phone fields when you want to evaluate a product before committing.
Platforms with strict anti-fraud requirements, particularly financial services and regulated industries, are more likely to screen against shared numbers. For those, the paid private number tier is more reliable. For the broader category of consumer apps and email providers where phone verification is a basic friction-reduction step, free shared numbers work consistently.
Developers can also integrate directly via the REST API to automate OTP retrieval in CI pipelines and QA test suites, removing the manual browser step entirely.
Available number countries and how numbers are managed
asms.ai currently lists public numbers from the United States, United Kingdom, Germany, Georgia, Ukraine, and additional countries as new number stock becomes available. The country displayed beside each number is the registration country, which matters when a platform only accepts numbers from a specific region.
ProtonMail does not impose a country restriction on phone verification, so you can use a US, UK, German, or any other listed number regardless of where you are physically located.
Inboxes are wiped periodically to keep them readable and to prevent old codes from cluttering the view. After a wipe the number itself stays active and continues receiving new messages normally. Numbers that are retired from the list are replaced by fresher alternatives on a rolling basis. If a number you used previously is no longer listed, picking any other active number from the same or a different country is all that is needed.