Write it all down.Show it tono one, or anyone you choose.
A private journal, encrypted on your device. Every entry is yours alone until you choose to share one: with friends, your followers, or the world.
Free, in your browser, no account.
We can’t read your notes.Not now, not ever.
Not us, not a breach, not a subpoena. Only your passphrase opens your words.
Every entry is encrypted in your browser before it touches the disk. No server ever sees your words. Watch it happen.
On disk
…
Real AES-256-GCM, run in your browser just now with a key made for this page. shown as hex. Type in the box: every keystroke is sealed again under a fresh nonce, so even the same sentence never lands the same way twice.
Encrypted before it touches the disk
The key comes from your passphrase and never leaves your device.
Kept on your device, not ours
No account, no cloud, no telemetry. Sync carries only ciphertext.
Readable even if Posthum disappears
Export any time. One public-domain file opens your backup with your passphrase alone.
Forget your passphrase and lose your recovery key, and even we cannot bring it back. That is the price, and the proof.
Share one entry.
Keep the rest.
A place for the thought before you lose it. Write it down, then decide who gets to read it. Just you is always an option.
Tap a destination or drag the handle.
This is a demo. Your note is never saved or shared.
One entry, one audience. Choose a destination and confirm. Everything else stays yours.
Every note out therewas typed.
People write here. Machines are for reading it back to you — never for filling the page.
A note carries the mark when every character of it was typed into the page. Paste something in and the note keeps the words but loses the mark, for good — and the mark, or its absence, travels with the note wherever you throw it.
Written, not generated
Nothing is blocked and nobody is locked out — paste what you like into your own journal. What a shared note says about itself is simply true.
Reading is the AI’s job
Reflection runs on a key you bring, one entry at a time, only when you press the button. It never writes into the page.
A claim, plainly labelled
The mark is your copy of Posthum saying what it saw. It takes the price of flooding a feed from nothing up to a line of script; it does not pretend to be proof, and every page that shows it says so.
A journal that doesmore than keep.
Seal a letter for a date you choose, a year out or forty. It stays hidden, stamped with the month it opens. Click the seal to open this one.
Sealed letters
To your future self, or someone you name. Opens on the day, and only then.
Legacy
A few entries that outlive you, released to someone you name, on your terms.
Reflect, with an AI you choose
Bring your own key. Nothing is sent until you press the button and see what goes.
On this day
What you wrote a year ago today, back above the page while you write.
Search, tags, mood
Find the entry, not the date. Search runs in your browser, like everything else.
Export, any time
An encrypted backup that opens without us, or plain Markdown.
Sealed 2024 · for your future self · SEP 2026
A letter for you.
Free to keep.Pay to carry it across devices.
No ads, no trackers. Sync pays for the storage that holds your encrypted journal.
Forever free
One device. Yours, completely.
$0/forever
- The full private journal: capture, search, tags, mood
- Sealed letters to your future self
- Encryption on your device, always
- Encrypted backup export (.posthum) and plain Markdown
- Bring-your-own-key reflection
Carry it with you
Every device. Every audience.
$4/month · or $39/year
- Encrypted sync across your devices
- Share single entries with friends you name
- Share single entries with your followers
- Publish single entries to the world
- Sealed letters delivered by email on the open date
- Legacy delivery, on your terms
Start tonight.Keep it forever.
Free, in your browser, no account to make. Sync is a few dollars a month when you want every device, encrypted the whole way.