It has happened to all of us, I’m sure. You hit “send,” only to realize autofill has provided the wrong address. Or, you “reply all” when you meant your response to be private. How many times have you said to yourself, “If only I could unsend that email”?

Now you can. Two Harvard Law School students, Lindsay Lin and David S. Gobaud, have launched a free service, Pluto Mail, that allows users to unsend emails after they’ve been sent. It also allows users to edit emails after they’ve been sent (but before they’ve been opened), set auto-expiration dates that make the text of an email disappear, and track when emails are opened.

PlutoBetaEven better, the service works with your current email client and email address. And it does so without requiring downloads or plugins for either the sender or the recipient.

For example, if you use Outlook for email, you set it up to use Pluto Mail in the same way that you would add any new email account. (The Pluto Mail site provides detailed instructions for all major email clients.) Once it’s set up, you can use toggle between sending email through your standard account or through Pluto Mail, or you can use Pluto Mail as your default. Either way, the recipient sees it as coming from your standard email address and all replies go to your standard address.

Alternatively, you can send emails from a compose page within Pluto Mail. The emails will still show as coming from your email address and replies will still go to your email address.

Settings for email must be configured through the Pluto Mail site. By default, emails are set to expire seven days after they are sent or three days after they are opened, but you can change this so they never expire.

Unsending and Auto-Expiring Email

Once you’ve set up your account, you can “unsend” an email by logging in to the Pluto Mail website. You will see a column displaying your sent emails. Find the message you want to retract, click the “unsend” link, and you’re done. The email and subject line remain in the recipient’s inbox, but the text is replaced with the message, “This message has expired.”

The same occurs if you set an email to automatically expire. You can set the days, hours and minutes after which the email should expire, with different deadlines for after it is sent and after it is opened. Once the expiration point arrives, the text of the email is replaced with the expiration message. If the recipient forwarded your email to others, it will expire for them as well.

Pluto Mail’s email management dashboard also lets you see the date and time an email was opened and by what email address.

Not Foolproof

Unfortunately, Pluto Mail is not foolproof. The way it works is to convert the text of your email into an image. For the recipient, it looks like text, but it is actually an image file. Presumably, Pluto Mail stores the image and when an email is unsent, it replaces the image with one that contains the expired message.

Thus, it seems to me that a recipient could retain the text simply by saving the image file elsewhere. Even if the email is unsent, the image file remains saved. I tried that and it worked. I sent an email from one of my email addresses to another. I opened the received email and saved the image as a file on my desktop. I then logged into Pluto Mail and unsent the message.

While I could no longer read the message in my email client, I could still read it in the image file I’d saved on my desktop (but without any header info or metadata).

Site in Private Beta

The two Harvard Law students who founded Pluto Mail both have backgrounds in technology, according to The Harvard Crimson. David Gobaud is a 2010 Stanford computer science graduate who worked for Google and in the White House before going to law school. Lin has a 2012 mathematics degree from the University of Virginia and has been creating websites since grade school. You can see a TV interview with Gobaud via WGBH in Boston.

For now, there is a waitlist to register for the service. You can sign up for the waitlist at the site’s home page. I was able to register last night and I now have 10 invites to pass on to others, so let me know if you’d like one.

Photo of Bob Ambrogi Bob Ambrogi

Bob is a lawyer, veteran legal journalist, and award-winning blogger and podcaster. In 2011, he was named to the inaugural Fastcase 50, honoring “the law’s smartest, most courageous innovators, techies, visionaries and leaders.” Earlier in his career, he was editor-in-chief of several legal publications, including The National Law Journal, and editorial director of ALM’s Litigation Services Division.