⏳ Zero-Knowledge Time Capsule

Write it now.
Read it on the right day.

Your message is encrypted in your browser right now. You choose when the link unlocks — 1 year, 5 years, on their 18th birthday, on your wedding anniversary. Before that date arrives, the link returns nothing. Not even we can read it.

Letter to future self ✍️For your child on their 18th 👶Wedding anniversary 💍Graduation day 🎓Business prediction 📈

0 chars · encrypted locally

Unlocks on: Tuesday, May 4, 2027

Encrypted in your browser · Opens automatically on the unlock date

What people put in their time capsules

The most emotionally powerful messages are the ones that took 30 minutes to write

✉️

Letter to future self

Open in 1 year or 5 years

"Dear future me, it's [date]. I'm writing this because I want you to remember who you were when you made this decision..."

🎓

Graduation day message

Open when they graduate

A parent writes something when their child is 10. The child opens it on graduation day — or the day they leave for college.

💒

Wedding anniversary

Open on anniversary

Written on the wedding day. Opened on the 25th anniversary. A time-locked message about hopes, promises, and what you believed love meant that day.

👶

To your child on their 18th birthday

Open on 18th birthday

Written the day they were born. The most personal gift they'll ever receive: your actual thoughts from the day they arrived in the world.

📈

Business prediction

Open in 5 years

A founder writes their vision for where the company will be in 5 years. The team opens it on the company's 5th anniversary. Accountability through time.

🔐

Emergency instructions

Pair with Dead Man's Switch

Confidential information your family needs if something happens to you — but that you can't leave in plaintext anywhere. Opens automatically if you're unreachable.

How it actually works

Write & encrypt now

Your message is AES-256-GCM encrypted in your browser. We receive only the ciphertext — we cannot read it today, tomorrow, or ever.

Set the unlock date

Choose any future date. The link is valid from that moment forward. Before the date, the server returns nothing — even if someone has the URL.

It opens only then

On the chosen date, the link activates. When the recipient opens it, the message decrypts in their browser and is permanently deleted from our servers.

The guarantee you need to trust

The URL fragment (everything after # in the link) contains the decryption key. According to the HTTP specification, URL fragments are never transmitted to the server. They exist only in the browser.

This means: even if our servers were seized, subpoenaed, or hacked — the ciphertext stored on them is permanently meaningless without the key that was never sent to us.

The "unlock date" is also enforced server-side: the server will not return the ciphertext before the specified timestamp, even if presented with a valid URL.