Seal something for someone else

How do I make a capsule for a friend?

Choose For someone, type their name and yours, and pick when it opens: their birthday, New Year, graduation, in one year, or another date. The guesses become "Guesses about {name}" and the letter starts "Dear {name},". After sealing, Sealday offers to send the capsule link, and a seal card with no contents on it.

What does the recipient get?

A link to a sealed envelope: "From {you}, opens on {date}" with a countdown. In the app they can keep it, get a reminder and seal one back. On the open date, the full ceremony runs in the app. A web viewer can also open it in a browser, so they are never forced to install anything.

What does the recipient do, step by step?

A recipient who got a .sealday file instead of a link opens it from Files, or from You > Open a Sealday link or file. Links can also be pasted there.

1. They tap the link in the messenger. It opens Sealday, or the web viewer if the app is not installed.
2. They see the envelope: "From {you}", the open date and a countdown.
3. In the app they tap Keep it. Sealday saves the capsule and schedules a reminder for the day.
4. They can tap Seal one back to write a capsule in return, for you or for someone else.
5. On the open date they hold the seal to break it, or press Open it here in the viewer.

What does the web viewer do?

It is a static page on sealday.app with no server code behind it. Before the date it shows the envelope and countdown, offers an Add to Calendar file and points to the app. After the date it can open the capsule in the browser, using the same public beacon and the same check against the network key as the app.

The viewer needs no account, sets no cookies and uses no analytics. The capsule sits after the "#" in the address, which the browser keeps on the device.

What is visible and what is private?

The names and the open date are readable on the envelope by anyone with the link, and Sealday tells you so before you seal. The content is encrypted. The capsule travels in the part of the address after the "#", which browsers never send to a server, so Sealday's website never receives it.

Can I open it myself later?

No. A capsule you send is marked "Sent" and has no spare key on your phone, so it cannot be opened by you either. That is what makes the promise honest.

What can go wrong, and what are the limits?

Three limits are worth knowing before you send something important.

• The link is not tied to a person. Anyone who receives it can open the capsule on the date, so send it only to the people you mean.
• You cannot unsend it. Deleting the capsule on your phone does not cancel copies of a link already shared.
• Messengers sometimes cut long links. When that happens the recipient sees "This link looks incomplete" and should ask you to send it again, and Send the link again on the capsule screen resends it.
• The letter is limited to 1,500 characters and ten guesses on a link. Photos and voice need a sealed file, which needs Plus.

Which occasions work well?

A capsule for someone else is most fun when the date means something to them.

• Their birthday next year, with five guesses about their year
• A graduation, with a letter for the day they finish
• A wedding or a move, opening on the first anniversary
• New Year, sent to a friend as a joke prediction
• A "seal one back" reply that opens on your birthday

What should I write for someone else?

Write the way you would to them in person. Mention a memory only the two of you share, make a guess about their year, and end with a question they can answer when they open it. The letter field starts with "Dear {name}," so you can begin at once.

• Keep guesses kind. Pick things they would be happy to be wrong about.
• Include the date and one detail from today so the opening has a context.
• If it is a joke prediction, say so in the first line.
• Write for the person they will be then, not only for who they are now.

What are the steps?

1. Tap Seal, then For someone.
2. Enter their name, your name and the occasion.
3. Write the letter and guesses.
4. Review and hold to seal.
5. Send the link from the share sheet, or the file if you have Plus.