We keep it safe until the day, and we tell you plainly how.

1. You can take everything out, any time

From your private link you can download your capsule as a file: its details, who it goes to, and every letter you wrote. Each person who wrote a letter can download their own from their link. You don't need to ask us.

2. If we ever close, we deliver early

If Kept Letter has to shut down, we will email every capsule owner at least 60 days before, then deliver every capsule to its recipients ahead of its date, rather than let it disappear.

3. Pay once

Capsules that open within a year are free, and so is a text-only letter from one writer for up to 25 years. Photos and group capsules further out are paid once, and that price covers storage for the whole wait, up to 100 years. There is no subscription to lapse.

4. Sealed means sealed

Before the opening date, nobody can read the letters through Kept Letter, including the person who started the capsule. The organizer sees who has written, not what. Each writer can change, remove or download their own letter until the capsule is sealed, and download it any time after.

5. Recipients choose

On the day, each recipient gets an email and decides whether to accept the capsule. If they decline, nothing is shown to them and the sender isn't told why.

6. How it is kept, in detail

• Encrypted at rest. Letters, photos and voice notes are stored with our database provider, Supabase, in Tokyo, Japan, encrypted at rest. Photos and voice notes sit in private storage and are shown only through links that expire after an hour.
• A fingerprint at sealing. When a capsule is sealed we record a SHA-256 fingerprint of its contents. Each time the capsule's page is opened, the contents are checked against it.
• A second copy elsewhere. Every sealed capsule is also copied to Backblaze B2, a separate storage provider in the United States, encrypted and locked against changes. We read the copy back and compare it with the fingerprint, and check it again regularly.
• Emails that don't go through. On the day we email every address listed for each recipient, up to three per person. If sending fails, we try again every hour until it is accepted. The recipient's link keeps working after the day.

7. Why one payment can cover the wait

Photos are resized when they are added, and each capsule has a limit: 30 photos for a Keepsake, 300 for a Gathering. Videos are kept to 30 seconds and 30 MB each, and only plans with video can hold them, priced for the extra space. At today's storage prices, keeping a full Keepsake for 100 years costs us about a dollar, and a full Gathering several dollars. Capsules that open more than 25 years from now cost more, and a little more for each year past 50, because they ask more of us. We keep capsules for 100 years at most, and $3 of every payment goes into a reserve used only to keep capsules running and delivered. We can't promise any company lasts for decades, which is why promise 2 exists.

8. If Kept Letter changes hands

If another company ever takes over Kept Letter, capsules move to it only if it keeps every promise on this page. If it won't, we deliver capsules early, as in promise 2, instead of handing them over.

Who makes these promises

Kept Letter is run by DOPPO, a small company being set up in Tochigi, Japan. Questions: contact us.