Have you ever fired off an ill-considered email and then thought oops! the moment you hit Send? Or have you sent off an email intended to impress the recipient, realizing with horror, seconds too late, that you have misspelled their name? And the “Reply all” button has been a recipe for far too many disasters.
Whatever the reason, Undo Send is one of the most popular features requested by ProtonMail users. It is now automatically enabled for all our users in the beta.protonmail.com web interface, and provides a variable length second window during which you can opt to cancel sending an email.
How to use Undo Send in ProtonMail
When you send an email, the email composer window will close and you will see a banner at the top of your screen which says “Message sent. Undo.”
If you click the Undo button within the specified time limit, the composer window will reopen and you can continue editing the draft email.
Undo Send is enabled by default with a 10-second timer . You can change the timer duration from 0 seconds (i.e. Undo Send disabled) to your preferred timer length by going to Settings -> General -> Messages -> Undo Send.

A core part of our mission is to design tools that are secure, protect your privacy, and are also easy to use. To that end, we hope Undo Send will make ProtonMail more convenient and useful for you, and we look forward to hearing your feedback on this and other features in the ProtonMail Version 4.0 beta.
Undo Send FAQ
Who can use Undo Send?
Undo Send is available to all ProtonMail users.
Which platforms is Undo Send available on?
Undo Send is initially available on our beta.protonmail.com web app. It will also be included in upcoming versions of our iOS and Android apps.
Do I need to enable the feature?
No. Undo Send is automatically enabled for all ProtonMail users with a default timer delay of 10 seconds.
Can I change the timer delay settings?
Yes. To change the timer length, go to Settings -> General -> Messages -> Undo Send and select your preferred timer length from the drop-down menu. Setting the timer to 0 seconds disables the feature.
Can I recall the email after the timer period is over?
No. Undo Send only delays sending an email for a few seconds. It cannot recall an email once it has been sent. (However, our self-destructing emails feature does provide a related functionality.)
You can get a free secure email account from ProtonMail here.
We also provide a free VPN service to protect your privacy. ProtonMail and ProtonVPN are funded by community contributions. If you would like to support our development efforts, you can upgrade to a paid plan. Thank you for your support.
Updated Jan. 13, 2021.
2 comments on “ProtonMail now offers Undo Send, letting you cancel outgoing emails”
That’s a great feature.
But I think it would be great to delay e-mail for a specific time. So you can (optionally) specify while writing when the mail will be sent.
Best wishes
Thanks for the suggestion Andy, I’ll share it with our team.