Messenger

A messenger that behaves like one — and forgets on schedule

Every single message is fully encrypted — text, reaction, voice note or attachment — on your device, before it leaves. There is no way to send an unencrypted one, and no one can read it, including us. How the encryption works →

Around that: reactions, emoji, stickers, delivery ticks, typing — plus two things ordinary messengers do not give you: a timer that deletes on both sides, and an Unsend that actually removes the message from the other person's device.

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Any modern browserOpen web app Coming soon to the App StoreiPhone & iPad Coming soon to Google PlayAndroid

One conversation

Everything on this screen was encrypted before it left the phone

Encrypted chat showing reactions, a self-destruct banner, an unsent message and a countdown

Detail — 2.4×

1Self‑destruct, announcedWhen someone sets a timer, the chat says who set it and to what. Either side can change it.

2Reactions, encryptedSix to choose from. Each travels inside an encrypted message like any other.

3Unsent, on both devicesWithin an hour of sending you can take a message back. The other person sees “Unsent”, not the text.

4Counting downEach message shows how long it has left. At zero it is gone from both devices.

After you press send

Three ways to take something back

All three are encrypted instructions to the other device — not something we do for you on a server.

Self‑destruct timerAfter read, or after sent. Off, 30 seconds and up to a month.

UnsendRight‑click your own message within the hour. The reactions live in the same menu.

No ambiguity“It will be removed for both of you and replaced by ‘Unsent’. This cannot be undone.”

DestroyOn a message sent to you the menu offers Destroy instead — it removes the message from both devices.

What the other side seesWhere the message was, “Unsent” and the time. Nothing else.

The ordinary parts

Emoji, voice, typing — encrypted like everything else

A full emoji picker with categories, search and your frequently used set — it shares one tray with the stickers. Voice notes recorded in the chat and sent as encrypted attachments. Typing indicators and delivery ticks in one‑to‑one chats.

The emoji picker open over an encrypted chat

Stickers

Stickers. Sent as a name, never as a picture.

Four packs of Ki Friends ship inside the app, one of them animated. When you send a sticker, the message carries only which one it is — pack, number, version — inside the same end‑to‑end encrypted message as your text. No image is uploaded, attached or stored for the send. The other device already has the art and draws it.

An encrypted one-to-one chat with four stickers and two text messages, sent from both sides

1No bubbleA sticker stands on its own, like a real sticker on a page. Sent stickers sit on the right, received ones on the left.

2Drawn on this deviceWhat arrived was three short tokens inside the encrypted message. This device looked the art up in its own bundle.

3Time underneathThe time and delivery ticks sit under the sticker, where a bubble would show them. Timers and reactions apply as to any message.

4One word in the listThe chat list says “Sticker”, with a small sticker icon. It does not show the picture.

One tray: Emoji | StickersThe smiley next to the text field opens both. A pack's stickers, with search and a recents tab.

Suggested while you typeType “thanks” and the matching stickers appear above the box. Matching runs on your device, against the packs' own keywords.

Settings → StickersTwo switches: suggest while typing, double‑tap to send. Reorder or remove under My packs; add under From Private.Ki.

Preview, then sendTap a sticker to see it large, with its pack and name. Send, or mark it a favourite. The tray stays open.

Packs you have not added yetThey sit greyed at the end of the tab row. One tap adds a pack and opens it. Adding sends nothing to the server.

In a groupA sticker in a group carries the sender's name, like any group message. Encrypted once per member.

Meet the Ki Friends

Seven Ki Friends. Four packs. Forty stickers each.

Every sticker is one of the Ki Friends. Five of them have their packs; Tinny and Cipher are drawn and waiting for theirs.

Ki, a yellow key with a face, waving — KiThe yellow key. Greetings, thanks, moods and a few working days.Ki Basics

Snoop, a raccoon in a trench coat with binoculars — **Snoop**The raccoon with binoculars. Always looking, never finding.Snoop vs Nobody

Nobody, a blindfolded ghost, meditating — **Nobody**The blindfolded ghost. Sees nothing, knows nothing, says so.Snoop vs Nobody

Locke, a blue padlock with a face, thumbs up — **Locke**The padlock. Short answers, ending in a full stop.Office Hours

Pip, an envelope with a wax seal, cheering — **Pip**The envelope. Did it send? Delivered! Reply all?!Office Hours

Tinny, a hedgehog in a crumpled tinfoil hat, pointing — **Tinny**The hedgehog in the foil hat. They're listening. Sometimes he is right.Pack to come

Cipher, a black cat with green eyes, speaking in symbols — **Cipher**The black cat. Speaks only in symbols. Judges from the table.Pack to come

packs, built in

160

stickers

images uploaded

How it stays private

A sticker is a reference to art that is already on both devices. The reference travels inside the encrypted message, so it is protected exactly like your text: our server stores ciphertext, not which sticker you chose. Nothing is fetched from a server to show it, and adding a pack or choosing a favourite is recorded on your device only.

The technical detail

Inside the encrypted message the app writes one header, X-PKI-Sticker: <pack>/<number>/<version> — for example ki-basics/03/1 — and a one‑line body, [Sticker: Ki Basics – Thank you], which is what a reader without the art sees. There is no attachment and no image data. The receiving app reads the header and draws the sticker from its own bundle. The animated pack (Ki Basics Animated) is the same: the loop is already on the device, the message carries the same three tokens, and a device that cannot play it, or has motion reduced, shows the still.

Phone: an encrypted chat with stickers from both sides and text between them — **On the phone**The same conversation. Stickers without bubbles, time underneath.

Phone: the sticker tray open below the composer, with Emoji and Stickers tabs — **The tray**Stands where the keyboard was. Emoji | Stickers, search, packs.

Phone: the chat list with a row whose last message reads Sticker — **The chat list**“Sticker”, and a lock. Not the picture.

Voice messages

Hold, talk, listen back, send

The microphone sits next to the text field. Hold it to record; release to review. Nothing is sent until you say so, and what is sent is an encrypted attachment — our server sees a size, not a sound.

RecordingThe composer becomes a recording bar for as long as you hold.

Review before sendingPlay it back, discard it, or send it.

ReceivedA voice bubble with a play button and a duration, decrypted on this device.

PlayingProgress shown in the bubble. Timers and reactions apply to voice messages like any other.

Phone chat while holding the microphone to record — **Hold to record**Thumb down, talk, let go.

Phone chat with the recording locked for hands-free use — **Locked**Lock a longer recording and put the phone down.

On the phone

Long‑press a message. Reactions, Unsend, timer, emoji — one thumb.

The same controls as on the desktop, arranged for a hand. Unsend is there for your own messages within the hour; a message sent to you gets Destroy instead, which removes it on your side.

Phone: long-press menu with a strip of six reactions and Unsend — **Long‑press menu**Six reactions along the top, Unsend below — on your own messages, within the hour.

Phone: quick reaction strip above a message — **Quick reactions**Tap one; it travels encrypted, like a message.

Phone: self-destruct picker with Off, 30 s, 1 min, 10 min, 1 h, 1 day, 1 week, 1 month — **Self‑destruct picker**Off · 30 s · 1 min · 10 min · 1 h · 1 day · 1 week · 1 month. After read, or after sent.

Phone: emoji picker open above the composer — **Emoji picker**Categories, search, frequently used. Emoji are text and are encrypted with the message.

Phone: an encrypted one-to-one chat — **A conversation**Delivery ticks and reactions, as on the desktop.

Phone: the chat list — **The chat list**A lock on every row.

Phone: an encrypted group chat — **A group**Named, coloured senders; one key per member.

Starting a conversation

One sheet: an address you know, a new group, or an invitation

New chat offers the addresses you have written to, a new group, and “invite with a link or QR code” for someone who is not on Private.Ki yet. The guest gets their own account and key; the chat with them is encrypted like any other.

New chatRecipient autocomplete at the top; New group and Invite below.

A chat with someone you invitedOnce they have accepted, it is an ordinary encrypted chat — timer, reactions, Unsend and all.

Invitations and groups, in detail →

What this means for us

We deliver a payload. We do not know it was a 😂.

Reactions, unsend and destroy instructions, timers, voice notes, emoji and stickers all travel as encrypted messages. Our server sees that something went from one address to another, and how big it was. The full list is here.