Private by construction

Every conversation belongs to the people in it.

Message one person, bring a group together, or open a channel for just the people who need it. Kintrel encrypts the conversation on participant devices before the relay carries it.

Get Kintrel Open web client

Client-side encryption
Invite-only groups
Restricted channels

SECURE ROUTE THUREOS / E2EE

Your device Encrypts locally

Relay Ciphertext only

Their device Decrypts locally

READABLE MESSAGE CONTENT 0 BYTES

Groups with real boundaries

Bring everyone together. Narrow the room when it matters.

Kintrel groups grow by invitation. Inside them, a channel is a restricted subgroup with its own member list and encryption—not a label on a conversation everyone can read.

INVITE-ONLY GROUP 6 MEMBERS

Field Team Encrypted group

ACTIVE

Main channelEveryone in Field Team
6
LogisticsRestricted membership
4
LeadershipRestricted membership
2

A channel is not listed to parent-group members outside its roster.

Invite, then decide

Invitations arrive privately with the context needed to accept or decline. Declining does not announce a reason to the group.

One key chain per sender

Sender-key encryption protects group messages, and membership removal triggers key rotation so removed members do not receive future content.

Channels and @mentions

Keep the main conversation close, switch into focused channels, and address the right person without exposing mention targets to the relay.

Group and channel support follows the client release and platform capabilities shown on the downloads page.

What the relay knows

Enough to deliver. Not enough to read.

Kintrel’s store-and-forward service routes an opaque envelope to the right device. The keys that open it stay with the participants.

Relay can process

Encrypted message envelopes
Public key material
Delivery and routing metadata
Group and channel titles and rosters

Relay never receives

Message plaintext
Your private encryption keys
Unencrypted attachment contents

Read the plain-language privacy policy

Strong foundations

Modern protection, without the mystique.

A client-to-server implementation of a Signal-style design, built around the Thureos cryptographic core.

01
Establish

X3DH and PQXDH establish a session using public prekeys, including a post-quantum component.
02
Encrypt

The Double Ratchet protects one-to-one sessions, while sender-key chains protect groups. Encryption and decryption happen on client devices.
03
Deliver

The relay stores and forwards opaque ciphertext until a recipient device acknowledges it.

Explore how Kintrel protects a conversation

Privacy after decryption

Protection should stay visible and understandable.

Encryption protects content while it travels. Kintrel also makes the moments after decryption explicit, when your screen or another app can become the boundary.

BEFORE CONTENT LEAVES

Know when a file becomes an outside copy.

“Confirm before a file leaves Kintrel” is on by default. Opening, sharing, saving, or playing a decrypted file in another app asks first and explains what Kintrel can no longer control.

Turning warnings off does not weaken separate open/share restrictions for protected and disappearing messages.

PRIVACY SCREEN

Step away without leaving the conversation on display.

Desktop can cover Kintrel when its window becomes inactive. Mobile clients obscure app-switcher previews, and supported systems request screen-capture exclusion.

Sensitive messages relock on blur or background even when the optional desktop curtain is off.

MESSAGE CONTROLS

Protect one message—or let it disappear.

Require fresh device-owner authentication before revealing sensitive content, or set an absolute expiration that follows the message across supported devices.

These controls reduce exposure; they cannot stop another camera or a compromised recipient device.

Native clients, shared design

Meet people where you already work.

Move between supported native phone and desktop clients without moving the cryptographic boundary to the server. Each linked device participates as its own secure endpoint.

Choose your platform

Android
iPhone & iPad
Windows
macOS
Linux
Web

How Kintrel is made

One client experience, built across platforms.

Kintrel’s client experience is built with Kotlin®, Kotlin Multiplatform, and Compose Multiplatform.

Technology marks identify tools used by Kintrel; no affiliation or endorsement is implied.

Ready when you are

Say what you mean.
Keep it within the right circle.

Download Kintrel Open web app