> ## Documentation Index
> Fetch the complete documentation index at: https://docs.kynesys.xyz/llms.txt
> Use this file to discover all available pages before exploring further.

# Instant Messaging

> End-to-end encrypted, post-quantum messaging through the Demos SDK, with two client classes for two different delivery models.

# Instant Messaging

The Demos SDK ships **two** instant-messaging client classes under the `instantMessaging` namespace. Both use the same E2E encryption layer (`ml-kem-aes` for key encapsulation and AES-GCM, `ml-dsa` for the registration proof key), but they target different transports and delivery guarantees:

| Class               | Default port | Transport               | History                               | Offline delivery                               | Delivery acknowledgement                       | When to use                                                                                                      |
| ------------------- | ------------ | ----------------------- | ------------------------------------- | ---------------------------------------------- | ---------------------------------------------- | ---------------------------------------------------------------------------------------------------------------- |
| `L2PSMessagingPeer` | `3006`       | L2PS messaging server   | Yes — `history()` API with pagination | Yes — server queues messages for offline peers | Yes — `message_sent` / `message_queued` frames | Production. L2PS-backed messaging with persistence and L2PS pipeline (mempool → batch → L1 proof → L1 finality). |
| `MessagingPeer`     | `3005`       | Legacy signaling server | No                                    | No                                             | No                                             | Transient relay-only messaging. Kept for backwards compatibility.                                                |

The default reader of these docs should reach for **`L2PSMessagingPeer`**. Every code example below uses it unless explicitly labeled "legacy".

## Where to go next

<CardGroup cols={2}>
  <Card title="What is the Instant Messaging Protocol?" href="/sdk/websdk/instant-messaging/what-is-the-instant-messaging-protocol" icon="circle-question">
    The L2PS-backed protocol, plus how the legacy signaling-only path differs.
  </Card>

  <Card title="Architecture overview" href="/sdk/websdk/instant-messaging/architecture-overview" icon="sitemap">
    Port 3005 vs port 3006, and the L2PS pipeline.
  </Card>

  <Card title="Quickstart" href="/sdk/websdk/instant-messaging/quickstart" icon="bolt">
    Connect, send, receive, and read history with `L2PSMessagingPeer`.
  </Card>

  <Card title="API reference" href="/sdk/websdk/instant-messaging/api-reference" icon="book">
    Method-by-method reference for both classes.
  </Card>

  <Card title="Message types" href="/sdk/websdk/instant-messaging/message-types" icon="envelope">
    Wire-protocol message types for each class.
  </Card>

  <Card title="Encryption" href="/sdk/websdk/instant-messaging/encryption" icon="lock">
    The shared `ml-kem-aes` E2E layer.
  </Card>

  <Card title="FAQ" href="/sdk/websdk/instant-messaging/faq" icon="circle-question">
    Common questions, including which class to pick.
  </Card>
</CardGroup>