### Install XChat SDK dependencies

Source: https://docs.x.com/xchat/getting-started

Commands and configuration files to install the necessary SDK packages for various environments.

```bash
pip install chatxdk xdk
```

```bash
npm install @xdevplatform/chat-xdk @xdevplatform/xdk
npm install juicebox-sdk   # optional peer dependency; required for setup()/unlock() secure key backup
```

```toml
[dependencies]
# chat-xdk-core is not yet on crates.io; use the git dependency
chat-xdk-core = { git = "https://github.com/xdevplatform/chat-xdk" }  # pin a release tag in production, e.g. tag = "vX.Y.Z"
reqwest = { version = "0.12", features = ["blocking", "json"] }
serde_json = "1"
base64 = "0.22"

# Required until thrift 0.24 is released on crates.io
[patch.crates-io]
thrift = { git = "https://github.com/apache/thrift.git", rev = "deb36fa409849de45973b04ffc3ce49d277ca90a" }
```

```bash
go get github.com/xdevplatform/chat-xdk/go/chatxdk
```

```bash
dotnet add package XDevPlatform.ChatXdk
```

```xml
<dependency>
  <groupId>com.x</groupId>
  <artifactId>chatxdk</artifactId>
  <!-- Use the latest version from https://central.sonatype.com/artifact/com.x/chatxdk -->
  <version>x.y.z</version>
</dependency>
```

--------------------------------

### Install X Chat SDK dependencies

Source: https://docs.x.com/xchat/building-ui-apps-with-wasm

Install the required packages for the chat engine and secure key backup functionality.

```bash
npm install @xdevplatform/chat-xdk
npm install juicebox-sdk   # required for setup() / unlock() secure key backup
```

--------------------------------

### Register and Initialize Identity

Source: https://docs.x.com/xchat/getting-started

These examples demonstrate the flow of generating keypairs, registering them via the API, and setting the identity for the current session.

```python
from xdk.chat.models import AddUserPublicKeyRequest

registration = chat.generate_keypairs()
pk = registration.public_key
client.chat.add_user_public_key(
    "YOUR_USER_ID",
    AddUserPublicKeyRequest(
        public_key={
            "identity_public_key_signature": pk.identity_public_key_signature,
            "public_key": pk.public_key,
            "public_key_fingerprint": pk.public_key_fingerprint,
            "registration_method": pk.registration_method,
            "signing_public_key": pk.signing_public_key,
            "signing_public_key_signature": pk.signing_public_key_signature,
        },
        version=registration.version,
        generate_version=registration.generate_version,
    ),
)
chat.setup("YOUR_PASSCODE")
chat.set_identity("YOUR_USER_ID", str(registration.version or "1"))
```

```typescript
const registration = chat.generateKeypairs();
const pk = registration.publicKey;
await client.chat.addUserPublicKey('YOUR_USER_ID', {
  public_key: {
    identity_public_key_signature: pk.identityPublicKeySignature,
    public_key: pk.publicKey,
    public_key_fingerprint: pk.publicKeyFingerprint,
    registration_method: pk.registrationMethod,
    signing_public_key: pk.signingPublicKey,
    signing_public_key_signature: pk.signingPublicKeySignature,
  },
  version: registration.version,
  generate_version: registration.generateVersion,
});
await chat.setup('YOUR_PASSCODE');
chat.setIdentity('YOUR_USER_ID', String(registration.version ?? '1'));
```

```rust
let registration = chat.generate_keypairs()?;
let body = serde_json::to_value(&registration)?;
let resp = http
    .post(format!("https://api.x.com/2/users/{user_id}/public_keys"))
    .header("Authorization", &auth)
    .json(&body)
    .send()?;
if !resp.status().is_success() {
    anyhow::bail!("register keys: {}", resp.text()?);
}
let _blob = chat.export_keys()?; // store securely
let key_version = registration.version.clone().unwrap_or_else(|| "1".into());
chat.set_identity(&user_id, &key_version);
```

```go
registration, err := chat.GenerateKeypairs()
if err != nil {
    log.Fatal(err)
}
regJSON, _ := json.Marshal(registration)
req, _ := http.NewRequest(http.MethodPost,
    "https://api.x.com/2/users/"+userID+"/public_keys",
    bytes.NewReader(regJSON))
req.Header.Set("Authorization", "Bearer "+accessToken)
req.Header.Set("Content-Type", "application/json")
resp, err := httpClient.Do(req)
if err != nil {
    log.Fatal(err)
}
resp.Body.Close()
privateKeys, _ := chat.ExportKeys() // store securely
_ = privateKeys
keyVersion := "1"
if registration.Version != nil {
    keyVersion = *registration.Version
}
if err := chat.SetIdentity(userID, keyVersion); err != nil {
    log.Fatal(err)
}
```

--------------------------------

### Initialize Chat XDK with Existing Keys

Source: https://docs.x.com/xchat/getting-started

Examples for initializing the Chat XDK across multiple languages using either secure key backup or key blob imports.

```python
import json
from chat_xdk import Chat

resp = client.chat.get_user_public_keys(
    "YOUR_USER_ID",
    public_key_fields=[
        "public_key_version", "public_key", "signing_public_key",
        "identity_public_key_signature", "juicebox_config",
    ],
)
record = resp.data[0]
signing_key_version = str(record["public_key_version"])

chat = Chat(json.dumps(record["juicebox_config"]))
chat.unlock("YOUR_PASSCODE")  # recovers keys stored by setup() during first-time setup (step 3)
# Or load a key blob instead of secure key backup:
# chat.import_keys(blob, version=signing_key_version)
chat.set_identity("YOUR_USER_ID", signing_key_version)
```

```typescript
import { createChat } from '@xdevplatform/chat-xdk';

const resp = await client.chat.getUserPublicKeys('YOUR_USER_ID', {
  publicKeyFields: [
    'public_key_version', 'public_key', 'signing_public_key',
    'identity_public_key_signature', 'juicebox_config',
  ],
});
const record = resp.data[0];
const signingKeyVersion = String(record.public_key_version);

const chat = await createChat({
  juiceboxConfig: JSON.stringify(record.juicebox_config),
  getAuthToken: async (realmId) => getRealmTokenFromYourBackend(realmId),
});
await chat.unlock('YOUR_PASSCODE');
chat.setIdentity('YOUR_USER_ID', signingKeyVersion);
```

```rust
use base64::{engine::general_purpose::STANDARD as B64, Engine};
use chat_xdk_core::ChatCore;

let chat = ChatCore::new();
let blob = B64.decode(std::env::var("PRIVATE_KEYS_B64")?)?;
let signing_key_version = std::env::var("SIGNING_KEY_VERSION").unwrap_or_else(|_| "1".into());
chat.import_keys_with_version(&blob, &signing_key_version)?;
chat.set_identity("YOUR_USER_ID", &signing_key_version);
```

```go
import "github.com/xdevplatform/chat-xdk/go/chatxdk"

chat := chatxdk.New()
defer chat.Close()

blob, err := chatxdk.Base64ToBytes(os.Getenv("PRIVATE_KEYS_B64"))
if err != nil {
    log.Fatal(err)
}
signingKeyVersion := os.Getenv("SIGNING_KEY_VERSION")
if signingKeyVersion == "" {
    signingKeyVersion = "1"
}
if err := chat.ImportKeysWithVersion(blob, signingKeyVersion); err != nil {
    log.Fatal(err)
}
if err := chat.SetIdentity(myUserID, signingKeyVersion); err != nil {
    log.Fatal(err)
}
```

```csharp
using ChatXdk;

using var chat = new Chat();
var signingKeyVersion = Environment.GetEnvironmentVariable("SIGNING_KEY_VERSION") ?? "1";
chat.ImportKeys(Convert.FromBase64String(
    Environment.GetEnvironmentVariable("PRIVATE_KEYS_B64")!), signingKeyVersion);
chat.SetIdentity(myUserId, signingKeyVersion);
```

```java
import com.x.chatxdk.Chat;

String signingKeyVersion = Optional.ofNullable(System.getenv("SIGNING_KEY_VERSION")).orElse("1");
try (Chat chat = new Chat()) {
    chat.importKeys(Base64.getDecoder().decode(System.getenv("PRIVATE_KEYS_B64")), signingKeyVersion);
    chat.setIdentity(myUserId, signingKeyVersion);
}
```

--------------------------------

### Install Chat XDK via Package Managers

Source: https://docs.x.com/xchat/xchat-xdk

Commands to install the Chat XDK library for various supported programming languages.

```bash
pip install chatxdk
```

```bash
npm install @xdevplatform/chat-xdk
npm install juicebox-sdk   # optional peer dependency; required for setup()/unlock() secure key backup
```

```toml
[dependencies]
# chat-xdk-core is not yet on crates.io; use the git dependency.
# It exports both ChatCore and the async secure-key-backup Chat type.
chat-xdk-core = { git = "https://github.com/xdevplatform/chat-xdk" }  # pin a release tag in production, e.g. tag = "vX.Y.Z"

# Required until thrift 0.24 is released on crates.io
[patch.crates-io]
thrift = { git = "https://github.com/apache/thrift.git", rev = "deb36fa409849de45973b04ffc3ce49d277ca90a" }
```

```bash
go get github.com/xdevplatform/chat-xdk/go/chatxdk
```

```bash
dotnet add package XDevPlatform.ChatXdk
```

```xml
<dependency>
  <groupId>com.x</groupId>
  <artifactId>chatxdk</artifactId>
  <!-- Use the latest version from https://central.sonatype.com/artifact/com.x/chatxdk -->
  <version>x.y.z</version>
</dependency>
```

--------------------------------

### Initialize API client with OAuth 2.0 token

Source: https://docs.x.com/xchat/getting-started

Setup the API client using a user-provided OAuth 2.0 access token.

```python
from xdk import Client

client = Client(access_token="YOUR_OAUTH2_USER_TOKEN")
```

```typescript
import { Client } from '@xdevplatform/xdk';

const client = new Client({ accessToken: 'YOUR_OAUTH2_USER_TOKEN' });
```

```rust
let access_token = std::env::var("X_ACCESS_TOKEN")?;
let http = reqwest::blocking::Client::new();
let auth = format!("Bearer {access_token}");
```

```go
accessToken := os.Getenv("X_ACCESS_TOKEN")
httpClient := &http.Client{Timeout: 30 * time.Second}
```

```csharp
using var http = new HttpClient();
http.DefaultRequestHeaders.Authorization =
    new System.Net.Http.Headers.AuthenticationHeaderValue(
        "Bearer", Environment.GetEnvironmentVariable("X_ACCESS_TOKEN"));
```

```java
String accessToken = System.getenv("X_ACCESS_TOKEN");
HttpClient http = HttpClient.newHttpClient();
```

--------------------------------

### Encrypt and Send Messages and Reactions

Source: https://docs.x.com/xchat/xchat-xdk

Examples for encrypting messages, replies, reactions, and general data across multiple languages.

```typescript
const payload = chat.encryptMessage({
  conversationId,
  text: 'Hello',
  // Optional: entities, attachments, shouldNotify, ttlMsec
});
const body = {
  message_id: payload.messageId,
  encoded_message_create_event: payload.encryptedContent,
  encoded_message_event_signature: payload.encodedEventSignature,
};
// POST body to /2/chat/conversations/{id}/messages

// Preview derived from + embedded raw event so recipients can validate;
// add replyToCkces: [...] when the original used an older key version
const reply = chat.encryptReply({
  conversationId,
  text: 'Sounds good',
  replyToEvent: originalEventB64,
});

// Conversation and target derived from the raw event
const add = chat.encryptAddReaction({ emoji: '👍', targetEvent: originalEventB64 });
const remove = chat.encryptRemoveReaction({ emoji: '👍', targetEvent: originalEventB64 });

const nameCt = chat.encrypt('Group title', rawConversationKey);
const title = chat.decrypt(nameCt, rawConversationKey);
```

```rust
let payload = chat.encrypt_message(EncryptMessageParams::new(conversation_id, "Hello"))?;
// Send body: payload.message_id → message_id,
// payload.encrypted_content → encoded_message_create_event,
// payload.encoded_event_signature → encoded_message_event_signature

// Preview derived from + embedded raw event so recipients can validate;
// set params.reply_to_ckces when the original used an older key version
let reply = chat.encrypt_reply(EncryptReplyParams::new(
    conversation_id, "Sounds good", original_event_b64,
))?;

// Conversation and target derived from the raw event
let reaction = EncryptReactionParams::new(original_event_b64, "👍");
let add = chat.encrypt_add_reaction(&reaction)?;
let remove = chat.encrypt_remove_reaction(&reaction)?;

// conv_key: XChatConversationKey from extract_conversation_keys / decrypt_conversation_key
let name_ct = chat.encrypt("Group title", &conv_key)?;
let title = chat.decrypt(&name_ct, &conv_key)?;
```

```go
payload, err := chat.EncryptMessage(chatxdk.EncryptMessageParams{
    ConversationID: conversationID,
    Text:           "Hello",
})
// Send body: payload.MessageID → message_id,
// payload.EncryptedContent → encoded_message_create_event,
// payload.EncodedEventSignature → encoded_message_event_signature

// Preview derived from + embedded raw event so recipients can validate;
// set ReplyToCkces when the original used an older key version
reply, err := chat.EncryptReply(chatxdk.EncryptReplyParams{
    ConversationID: conversationID,
    Text:           "Sounds good",
    ReplyToEvent:   originalEventB64,
})

// Conversation and target derived from the raw event
reaction := chatxdk.EncryptReactionParams{Emoji: "👍", TargetEvent: originalEventB64}
add, err := chat.EncryptAddReaction(reaction)
remove, err := chat.EncryptRemoveReaction(reaction)

nameCt, err := chat.Encrypt("Group title", rawKey)
title, err := chat.Decrypt(nameCt, rawKey)
_ = payload
_ = reply
_ = add
_ = remove
_ = title
_ = err
```

```csharp
var payload = chat.EncryptMessage(new EncryptMessageParams(conversationId, "Hello"));
// Send body: payload.MessageId → message_id,
// payload.EncryptedContent → encoded_message_create_event,
// payload.EncodedEventSignature → encoded_message_event_signature

// Preview derived from + embedded raw event so recipients can validate;
// set ReplyToCkces when the original used an older key version
var reply = chat.EncryptReply(new EncryptReplyParams(conversationId, "Sounds good", originalEventB64));

// Conversation and target derived from the raw event
var reaction = new EncryptReactionParams(originalEventB64, "👍");
var add = chat.EncryptAddReaction(reaction);
var remove = chat.EncryptRemoveReaction(reaction);

var nameCt = chat.Encrypt("Group title", rawKey);
var title = chat.Decrypt(nameCt, rawKey);
```

```java
SendPayload payload = chat.encryptMessage(new EncryptMessageParams(conversationId, "Hello"));
// Send body: payload.messageId → message_id,
// payload.encryptedContent → encoded_message_create_event,
// payload.encodedEventSignature → encoded_message_event_signature

// Preview derived from + embedded raw event so recipients can validate;
// set replyToCkces when the original used an older key version
SendPayload reply =
        chat.encryptReply(new EncryptReplyParams(conversationId, "Sounds good", originalEventB64));
```

--------------------------------

### GET /2/activity/subscriptions

Source: https://docs.x.com/xchat/real-time-events

Lists existing durable activity subscriptions.

```APIDOC
## GET /2/activity/subscriptions

### Description
Retrieves a paginated list of all active durable subscriptions.

### Method
GET

### Endpoint
/2/activity/subscriptions
```

--------------------------------

### GET /2/activity/stream

Source: https://docs.x.com/xchat/real-time-events

Establishes a stream to receive real-time X Chat activity events.

```APIDOC
## GET /2/activity/stream

### Description
Listen for new X Chat messages and events in real time.

### Method
GET

### Endpoint
/2/activity/stream
```

--------------------------------

### Configure and Decrypt Chat Events

Source: https://docs.x.com/xchat/getting-started

Sets up signing keys and enables key caching to facilitate event decryption. Includes examples for both batch processing and individual live event handling.

```python
# Once per process: fill the signing-key store and enable the key cache
def signing_keys_for(user_id: str) -> list[dict]:
    resp = client.chat.get_user_public_keys(
        user_id,
        public_key_fields=[
            "public_key_version", "public_key", "signing_public_key", "identity_public_key_signature",
        ],
    )
    return [
        {
            "user_id": user_id,
            "public_key_version": r["public_key_version"],
            "public_key": r["signing_public_key"],
            "identity_public_key": r["public_key"],
            "identity_public_key_signature": r["identity_public_key_signature"],
        }
        for r in resp.data
    ]

chat.set_signing_keys(
    signing_keys_for("YOUR_USER_ID") + signing_keys_for("RECIPIENT_USER_ID")
)
chat.set_cache_keys(True)

# Initial load or pagination: batch decrypt. Conversation keys are
# extracted from the KeyChange events in the batch; per-event failures
# are collected in result["errors"], never raised.
result = chat.decrypt_events(all_events_b64)
for dm in result["messages"]:
    event = dm["event"]
    if event["type"] == "Message" and event["content"]["content_type"] == "Text":
        print(event["sender_id"], event["content"]["text"], event["verified"])

# Live traffic: one event at a time
def handle_payload(payload: dict):
    if payload.get("conversation_key_change_event"):
        # A rotation enters the key cache only after its signature
        # verifies, which is what decrypt_events does
        chat.decrypt_events([payload["conversation_key_change_event"]])
    event = chat.decrypt_event(payload["encoded_event"])  # raises on failure
    if event["type"] == "Message" and event["content"]["content_type"] == "Text":
        print(event["sender_id"], event["content"]["text"], event["verified"])
```

```typescript
// Once per process: fill the signing-key store and enable the key cache
async function signingKeysFor(userId: string) {
  const resp = await client.chat.getUserPublicKeys(userId, {
    publicKeyFields: [
      'public_key_version', 'public_key', 'signing_public_key', 'identity_public_key_signature',
    ],
  });
  return resp.data.map((r: {
    public_key_version: string;
    public_key: string;
    signing_public_key: string;
    identity_public_key_signature: string;
  }) => ({
    userId,
    publicKeyVersion: r.public_key_version,
    publicKey: r.signing_public_key,
    identityPublicKey: r.public_key,
    identityPublicKeySignature: r.identity_public_key_signature,
  }));
}

chat.setSigningKeys([
  ...(await signingKeysFor('YOUR_USER_ID')),
  ...(await signingKeysFor('RECIPIENT_USER_ID')),
]);
chat.setCacheKeys(true);

// Initial load or pagination: batch decrypt. Conversation keys are
// extracted from the KeyChange events in the batch; per-event failures
// are collected in result.errors, never thrown.
const result = chat.decryptEvents(allEventsB64);
for (const dm of result.messages) {
  if (dm.event.type === 'message' && dm.event.content?.contentType === 'text') {
    console.log(dm.event.senderId, dm.event.content.text, dm.event.verified);
  }
}
```

--------------------------------

### prepare_conversation_key_change

Source: https://docs.x.com/xchat/xchat-xdk

Generates a fresh conversation key, encrypts it for all participants, and signs the change. This is used for starting 1:1 conversations or rotating keys in existing conversations.

```APIDOC
## prepare_conversation_key_change

### Description
Generates a fresh conversation key, encrypts it for every participant using their public keys, and signs the change. Returns a `PreparedConversationChange` object containing the raw key, participant keys, and action signatures.

### Parameters
- **participants** (Array) - Required - List of participant objects containing user_id, public_key, and key_version.
```

--------------------------------

### Initialize and manage keys in Python

Source: https://docs.x.com/xchat/xchat-xdk

Demonstrates secure key backup for clients and raw key blob persistence for servers or bots.

```python
from chat_xdk import Chat

# Secure key backup (client)
chat = Chat(juicebox_config_json)
chat.setup("YOUR_PASSCODE")          # first time; generates keypairs
# chat.unlock("YOUR_PASSCODE")        # later sessions
chat.set_identity(user_id, version)  # version from add-public-key / get-public-keys response
reg = chat.get_public_keys()     # or registration fields from generate_keypairs

# Key blob (server / bot)
chat2 = Chat()
chat2.import_keys(secret_blob, version)
chat2.set_identity(user_id, version)
blob = chat2.export_keys()       # treat as a password
```

--------------------------------

### Initialize and manage keys in Go

Source: https://docs.x.com/xchat/xchat-xdk

Uses ImportKeysWithVersion for server-side key management.

```go
chat := chatxdk.New()
defer chat.Close()

// Prefer ImportKeys for servers; secure key backup unlock where supported
keyBlob, _ := chatxdk.Base64ToBytes(privateKeysB64)
if err := chat.ImportKeysWithVersion(keyBlob, version); err != nil {
    log.Fatal(err)
}
chat.SetIdentity(userID, version)
publics, err := chat.GetPublicKeys()
blob, err := chat.ExportKeys()
_ = publics
_ = blob
_ = err
```

--------------------------------

### Initialize and manage keys in Java

Source: https://docs.x.com/xchat/xchat-xdk

Uses try-with-resources for Chat instance management and standard key import/export methods.

```java
try (Chat chat = new Chat()) {
    chat.importKeys(privateKeyBytes, version);
    chat.setIdentity(userId, version);
    var publics = chat.getPublicKeys();
    byte[] blob = chat.exportKeys();
}
```

--------------------------------

### GET /2/chat/conversations/{id}/events

Source: https://docs.x.com/xchat/real-time-events

Retrieves events for a specific chat conversation.

```APIDOC
## GET /2/chat/conversations/{id}/events

### Description
Retrieves a list of events for a specific chat conversation.

### Method
GET

### Endpoint
/2/chat/conversations/{id}/events
```

--------------------------------

### Manage Activity Streams and Subscriptions with XDK

Source: https://docs.x.com/xchat/real-time-events

Demonstrates initializing the XDK client for activity streams and creating event subscriptions for specific users.

```python
from xdk import Client

# Stream (app token); exact helper names depend on your XDK version
stream_client = Client(bearer_token="YOUR_BEARER_TOKEN")
# for event in stream_client.activity.stream():
#     handle_payload(event)  # see "Decrypt with the Chat XDK" below

# Or create a subscription; requires user-context auth for the monitored user
client = Client(access_token="YOUR_OAUTH2_USER_TOKEN")
client.activity.create_subscription({
    "event_type": "chat.received",
    "filter": {"user_id": "USER_ID_TO_MONITOR"},
})
```

```typescript
import { Client } from '@xdevplatform/xdk';

// Creating a subscription requires user-context auth for the monitored user
const client = new Client({ accessToken: 'YOUR_OAUTH2_USER_TOKEN' });
await client.activity.createSubscription({
  event_type: 'chat.received',
  filter: { user_id: 'USER_ID_TO_MONITOR' },
});
// Stream: client.activity.stream() when available in your SDK version
```

--------------------------------

### Initialize and Use XChat XDK

Source: https://docs.x.com/xchat/xchat-xdk

Demonstrates the full lifecycle of initializing the chat session, configuring keys, and performing message operations.

```python
from chat_xdk import Chat

chat = Chat(juicebox_config_json)  # or Chat() + import_keys(blob, version)
chat.unlock("YOUR_PASSCODE")

# Session defaults: identity for signing, stored signing keys for
# verification, opt-in cache for conversation keys
chat.set_identity(my_user_id, signing_key_version)
chat.set_signing_keys(signing_keys)  # all participants
chat.set_cache_keys(True)

# Batch-decrypt the backlog; senders verify against the stored keys
result = chat.decrypt_events(raw_events)
for dm in result["messages"]:
    ev = dm["event"]
    if ev["type"] == "Message":
        print(ev["sender_id"], ev["content"]["text"])

# Decrypt one live event with the cached conversation key
event = chat.decrypt_event(one_event_b64)

# Encrypt and sign as the session identity, under the cached key
payload = chat.encrypt_message(event["conversation_id"], "Hi!")
message_id = payload.message_id  # SDK-generated; send as message_id
```

```typescript
import { createChat } from '@xdevplatform/chat-xdk';

const chat = await createChat({
  juiceboxConfig: juiceboxConfigJson,
  getAuthToken: async (realmId) => getRealmToken(realmId),
});
await chat.unlock('YOUR_PASSCODE');

// Session defaults: identity for signing, stored signing keys for
// verification, opt-in cache for conversation keys
chat.setIdentity(myUserId, signingKeyVersion);
chat.setSigningKeys(signingKeys); // all participants
chat.setCacheKeys(true);

// Batch-decrypt the backlog; senders verify against the stored keys
const result = chat.decryptEvents(rawEvents);
for (const dm of result.messages) {
  if (dm.event.type === 'message') {
    console.log(dm.event.senderId, dm.event.content?.text);
  }
}

// Decrypt one live event with the cached conversation key
const event = chat.decryptEvent(oneEventB64);

// Encrypt and sign as the session identity, under the cached key
const payload = chat.encryptMessage({ conversationId: event.conversationId!, text: 'Hi!' });
const messageId = payload.messageId; // SDK-generated; send as message_id
```

```rust
// chat_xdk_core::Chat + unlock(b"…").await, or ChatCore + import_keys_with_version

// Session defaults: identity for signing, stored signing keys for
// verification, opt-in cache for conversation keys
chat.set_identity(my_user_id, signing_key_version);
chat.set_signing_keys(signing_keys); // all participants
chat.set_cache_keys(true);

// Batch-decrypt the backlog; senders verify against the stored keys
let result = chat.decrypt_events(&raw_events, &[]);
for dm in &result.messages {
    if let Event::Message(msg) = &dm.event {
        println!("{}: {}", msg.meta.sender_id.as_deref().unwrap_or("?"), msg.text().unwrap_or(""));
    }
}

// Decrypt one live event with the cached conversation key
let event = chat.decrypt_event(one_event_b64, &Default::default(), &[])?;

// Encrypt and sign as the session identity, under the cached key
let payload = chat.encrypt_message(EncryptMessageParams::new(conversation_id, "Hi!"))?;
let message_id = payload.message_id; // SDK-generated; send as message_id
```

```go
chat := chatxdk.New()
defer chat.Close()
blob, _ := chatxdk.Base64ToBytes(privateKeysB64)
_ = chat.ImportKeysWithVersion(blob, signingKeyVersion)

// Session defaults: identity for signing, stored signing keys for
// verification, opt-in cache for conversation keys
chat.SetIdentity(myUserID, signingKeyVersion)
_ = chat.SetSigningKeys(signingKeys) // all participants
chat.SetCacheKeys(true)
```

--------------------------------

### Initialize and manage keys in C#

Source: https://docs.x.com/xchat/xchat-xdk

Uses ImportKeys for key persistence and SetIdentity for session configuration.

```csharp
using var chat = new Chat();
chat.ImportKeys(privateKeyBytes, version);
// or secure key backup setup / unlock when config is available
chat.SetIdentity(userId, version);
var publics = chat.GetPublicKeys();
var blob = chat.ExportKeys();
```

--------------------------------

### POST /2/chat/media/upload/initialize

Source: https://docs.x.com/xchat/media

Initializes the media upload process.

```APIDOC
## POST /2/chat/media/upload/initialize

### Description
Initializes a new media upload session.

### Method
POST

### Endpoint
/2/chat/media/upload/initialize
```

--------------------------------

### GET /2/activity/stream

Source: https://docs.x.com/xchat/real-time-events

Retrieves an activity stream of events using an app Bearer token. This is often the simplest method for bots to receive events.

```APIDOC
## GET /2/activity/stream

### Description
Retrieves an activity stream of events. Filter the results client-side for specific event types like `chat.received` or `chat.sent`.

### Method
GET

### Endpoint
/2/activity/stream

### Query Parameters
- **backfill_minutes** (integer) - Optional - Number of minutes to backfill.
- **start_time** (string) - Optional - Start time for the stream.
- **end_time** (string) - Optional - End time for the stream.
```

--------------------------------

### GET /2/chat/media/{conversation_id}/{media_hash_key}

Source: https://docs.x.com/xchat/media

Retrieves an encrypted media file from a specific conversation. The response body contains the ciphertext which must be decrypted using the conversation key corresponding to the event's key version.

```APIDOC
## GET /2/chat/media/{conversation_id}/{media_hash_key}

### Description
Downloads an encrypted media attachment from a chat conversation. The returned data is ciphertext that requires decryption using the conversation key associated with the specific key version of the message.

### Method
GET

### Endpoint
https://api.x.com/2/chat/media/{conversation_id}/{media_hash_key}

### Parameters
#### Path Parameters
- **conversation_id** (string) - Required - The ID of the conversation, where colons should be replaced with hyphens.
- **media_hash_key** (string) - Required - The unique hash key for the media attachment.

### Response
#### Success Response (200)
- **body** (binary) - The encrypted media content (ciphertext).
```

--------------------------------

### Initialize and decrypt events in Go

Source: https://docs.x.com/xchat/getting-started

Sets up signing keys and processes decrypted messages from batch or live events.

```go
// Once per instance: fill the signing-key store ([]SigningKeyEntry
    // from GET /2/users/{id}/public_keys) and enable the key cache
    if err := chat.SetSigningKeys(participantSigningKeys); err != nil {
        log.Fatal(err)
    }
    chat.SetCacheKeys(true)

    // Initial load: batch decrypt; per-event failures land in result.Errors
    result, err := chat.DecryptEvents(allEventsB64, nil)
    if err != nil {
        log.Fatal(err)
    }
    for _, dm := range result.Messages {
        if dm.Event.Type == "Message" {
            fmt.Println(dm.Event.AsMessage().Text())
        }
    }

    // Live traffic: a rotation enters the key cache only after its
    // signature verifies, which is what DecryptEvents does
    if keyChange != "" {
        chat.DecryptEvents([]string{keyChange}, nil)
    }
    event, err := chat.DecryptEvent(encodedEvent, nil, nil)
    if err == nil && event.Type == "Message" {
        fmt.Println(event.AsMessage().Text())
    }
```

--------------------------------

### Initialize and manage keys in Rust

Source: https://docs.x.com/xchat/xchat-xdk

Supports both secure key backup and raw key blob operations.

```rust
// chat_xdk_core::Chat: async secure key backup unlock, or ChatCore + import_keys
chat.setup(b"YOUR_PASSCODE").await?;
// chat.unlock(b"YOUR_PASSCODE").await?;
chat.set_identity(user_id, version);
let publics = chat.get_public_keys()?;
let blob = chat.export_keys()?;
chat.import_keys_with_version(&blob, version)?;
```

--------------------------------

### Initialize and decrypt events in Java

Source: https://docs.x.com/xchat/getting-started

Sets up signing keys and processes JSON-based event data.

```java
// Once per instance: fill the signing-key store (SigningKeyEntry list
    // from GET /2/users/{id}/public_keys) and enable the key cache
    chat.setSigningKeys(participantSigningKeys);
    chat.setCacheKeys(true);

    // Initial load: batch decrypt; per-event failures land in result.errors
    DecryptEventsResult result = chat.decryptEvents(allEventsB64, null);
    for (DecryptedMessage dm : result.messages) {
        if ("Message".equals(dm.event.path("type").asText())) {
            System.out.println(dm.event.path("content").path("text").asText());
        }
    }

    // Live traffic: a rotation enters the key cache only after its
    // signature verifies, which is what decryptEvents does
    if (keyChangeB64 != null && !keyChangeB64.isEmpty()) {
        chat.decryptEvents(List.of(keyChangeB64), null);
    }
    JsonNode evt = chat.decryptEvent(encodedEvent, (Map<String, byte[]>) null, null);
    if ("Message".equals(evt.path("type").asText())) {
        System.out.println(evt.path("content").path("text").asText());
    }
```

--------------------------------

### Set up conversation keys in Rust

Source: https://docs.x.com/xchat/getting-started

Prepare conversation key change parameters and perform an HTTP request to add keys in Rust.

```rust
// public_key_inputs: Vec<PublicKeyInput> from GET public keys
    // (user_id, public_key, key_version ← public_key_version)
    // New 1:1; set params.conversation_id = Some(id) to rotate later
    let prepared = chat.prepare_conversation_key_change(
        ConversationKeyChangeParams::new(public_key_inputs),
    )?;
    let participant_keys: Vec<_> = prepared
        .participant_keys
        .iter()
        .map(|pk| {
            serde_json::json!({
                "user_id": pk.user_id,
                "encrypted_conversation_key": pk.encrypted_key,
                "public_key_version": pk.public_key_version,
            })
        })
        .collect();
    let action_signatures: Vec<_> = prepared
        .action_signatures
        .iter()
        .map(|sig| {
            serde_json::json!({
                "message_id": sig.message_id,
                "encoded_message_event_detail": sig.encoded_message_event_detail,
                "message_event_signature": {
                    "signature": sig.signature,
                    "public_key_version": sig.public_key_version,
                    "signature_version": sig.signature_version,
                },
            })
        })
        .collect();
    let body = serde_json::json!({
        "conversation_key_version": prepared.conversation_key_version,
        "conversation_participant_keys": participant_keys,
        "action_signatures": action_signatures,
    });
    let resp: serde_json::Value = http
        .post(format!("https://api.x.com/2/chat/conversations/{recipient_id}/keys"))
        .header("Authorization", &auth)
        .json(&body)
        .send()?
        .json()?;
    // Canonical id for later requests
    let conversation_id = resp["data"]["conversation_id"].as_str().unwrap().to_string();
    // conversation_key is Option<XChatConversationKey>; encrypt_message wants owned bytes
    let conv_key = prepared.conversation_key.expect("key present").to_bytes();
    let conv_key_version = prepared.conversation_key_version;
```

--------------------------------

### Set up conversation keys in JavaScript

Source: https://docs.x.com/xchat/getting-started

Prepare a conversation key change and add keys to a recipient using the JavaScript client.

```javascript
// Omit conversationId for a new 1:1; pass the id to rotate later
    const prepared = chat.prepareConversationKeyChange({
      publicKeys: [
        await publicKeyInput('YOUR_USER_ID'),
        await publicKeyInput('RECIPIENT_USER_ID'),
      ],
    });
    const resp = await client.chat.addConversationKeys('RECIPIENT_USER_ID', {
      conversation_key_version: prepared.conversationKeyVersion,
      conversation_participant_keys: prepared.participantKeys.map((pk) => ({
        user_id: pk.userId,
        encrypted_conversation_key: pk.encryptedKey,
        public_key_version: pk.publicKeyVersion,
      })),
      action_signatures: prepared.actionSignatures.map((sig) => ({
        message_id: sig.messageId,
        encoded_message_event_detail: sig.encodedMessageEventDetail,
        message_event_signature: {
          signature: sig.signature,
          public_key_version: sig.publicKeyVersion,
          signature_version: sig.signatureVersion,
        },
      })),
    });
    const conversationId = resp.data.conversation_id; // canonical id for later requests
    const sequenceId = resp.data.sequence_id;
    const convKey = prepared.conversationKey;
    const convKeyVersion = prepared.conversationKeyVersion;
```

--------------------------------

### Perform chat operations in Java

Source: https://docs.x.com/xchat/xchat-xdk

Demonstrates session initialization, batch decryption, and message encryption using the Java SDK.

```java
try (Chat chat = new Chat()) {
    chat.importKeys(privateKeyBytes, signingKeyVersion);

    // Session defaults: identity for signing, stored signing keys for
    // verification, opt-in cache for conversation keys
    chat.setIdentity(myUserId, signingKeyVersion);
    chat.setSigningKeys(signingKeys); // all participants
    chat.setCacheKeys(true);

    // Batch-decrypt the backlog; senders verify against the stored keys
    DecryptEventsResult result = chat.decryptEvents(rawEvents, null);
    for (DecryptedMessage dm : result.messages) {
        if ("Message".equals(dm.event.path("type").asText())) {
            System.out.println(dm.event.path("content").path("text").asText());
        }
    }

    // Decrypt one live event with the cached conversation key
    JsonNode event = chat.decryptEvent(oneEventB64, (Map<String, byte[]>) null, null);
    String conversationId = event.path("conversation_id").asText();

    // Encrypt and sign as the session identity, under the cached key
    SendPayload payload = chat.encryptMessage(new EncryptMessageParams(conversationId, "Hi!"));
    String messageId = payload.messageId; // SDK-generated; send as message_id
}
```

--------------------------------

### Initialize and manage keys in TypeScript

Source: https://docs.x.com/xchat/xchat-xdk

Uses secure key backup for identity management; raw key export/import is not supported in JS/WASM environments.

```typescript
import { createChat } from '@xdevplatform/chat-xdk';

const chat = await createChat({
  juiceboxConfig: juiceboxConfigJson,
  getAuthToken: async (realmId) => getRealmToken(realmId),
});
await chat.setup('YOUR_PASSCODE');
// await chat.unlock('YOUR_PASSCODE');
chat.setIdentity(userId, version);
const publics = chat.getPublicKeys();

// JS/WASM stores keys only through secure key backup; there is no raw key
// export/import here. For key-blob persistence, use a native binding.
```

--------------------------------

### Prepare and register conversation keys in Python

Source: https://docs.x.com/xchat/getting-started

Fetches user public keys and registers a new conversation key with the API. Ensure all fetched keys are verified before use to prevent identity substitution.

```python
def public_key_input(user_id: str) -> dict:
    r = client.chat.get_user_public_keys(
        user_id, public_key_fields=["public_key_version", "public_key"]
    ).data[0]
    return {"user_id": user_id, "public_key": r["public_key"], "key_version": r["public_key_version"]}

prepared = chat.prepare_conversation_key_change(
    [public_key_input("YOUR_USER_ID"), public_key_input("RECIPIENT_USER_ID")],
    # conversation_id=None for a new 1:1; pass the id to rotate later
)
resp = client.chat.add_conversation_keys(
    "RECIPIENT_USER_ID",
    {
        "conversation_key_version": prepared["conversation_key_version"],
        "conversation_participant_keys": [
            {
                "user_id": pk["user_id"],
                "encrypted_conversation_key": pk["encrypted_key"],
                "public_key_version": pk["public_key_version"],
            }
            for pk in prepared["participant_keys"]
        ],
        "action_signatures": [
            {
                "message_id": sig["message_id"],
                "encoded_message_event_detail": sig["encoded_message_event_detail"],
                "message_event_signature": {
                    "signature": sig["signature"],
                    "public_key_version": sig["public_key_version"],
                    "signature_version": sig["signature_version"],
                },
            }
            for sig in prepared["action_signatures"]
        ],
    },
)
conversation_id = resp.data["conversation_id"]  # canonical id for later requests
sequence_id = resp.data["sequence_id"]
conv_key = prepared["conversation_key"]
conv_key_version = prepared["conversation_key_version"]
```

--------------------------------

### Prepare and submit conversation keys

Source: https://docs.x.com/xchat/getting-started

Prepares the conversation key change parameters and sends the resulting payload to the X API.

```go
// KeyVersion comes from the public_key_version field on each record
prepared, err := chat.PrepareConversationKeyChange(chatxdk.ConversationKeyChangeParams{
    PublicKeys: []chatxdk.PublicKeyInput{
        {UserID: myUserID, PublicKey: myIdentityPubB64, KeyVersion: myKeyVersion},
        {UserID: recipientID, PublicKey: theirIdentityPubB64, KeyVersion: theirKeyVersion},
    },
    // ConversationID empty for a new 1:1; pass the id to rotate later
})
var parts []map[string]string
for _, pk := range prepared.ParticipantKeys {
    parts = append(parts, map[string]string{
        "user_id":                    pk.UserID,
        "encrypted_conversation_key": pk.EncryptedKey,
        "public_key_version":         pk.PublicKeyVersion,
    })
}
var sigs []map[string]any
for _, sig := range prepared.ActionSignatures {
    sigs = append(sigs, map[string]any{
        "message_id":                   sig.MessageID,
        "encoded_message_event_detail": sig.EncodedMessageEventDetail,
        "message_event_signature": map[string]string{
            "signature":          sig.Signature,
            "public_key_version": sig.PublicKeyVersion,
            "signature_version":  sig.SignatureVersion,
        },
    })
}
body, _ := json.Marshal(map[string]any{
    "conversation_key_version":      prepared.ConversationKeyVersion,
    "conversation_participant_keys": parts,
    "action_signatures":             sigs,
})
req, _ := http.NewRequest(http.MethodPost,
    "https://api.x.com/2/chat/conversations/"+recipientID+"/keys",
    bytes.NewReader(body))
req.Header.Set("Authorization", "Bearer "+accessToken)
req.Header.Set("Content-Type", "application/json")
resp, err := httpClient.Do(req)
// Response data.conversation_id is the canonical id for later requests
_ = resp
convKey := prepared.ConversationKey
convKeyVersion := prepared.ConversationKeyVersion
```

```csharp
// KeyVersion comes from the public_key_version field on each record
var prepared = chat.PrepareConversationKeyChange(new ConversationKeyChangeParams(new[] {
    new PublicKeyInput { UserId = myUserId, PublicKey = myPk, KeyVersion = myVer },
    new PublicKeyInput { UserId = recipientId, PublicKey = theirPk, KeyVersion = theirVer },
})); // ConversationId null for a new 1:1; set it to rotate later
var keysBody = new {
    conversation_key_version = prepared.ConversationKeyVersion,
    conversation_participant_keys = prepared.ParticipantKeys.Select(pk => new {
        user_id = pk.UserId,
        encrypted_conversation_key = pk.EncryptedKey,
        public_key_version = pk.PublicKeyVersion,
    }),
    action_signatures = prepared.ActionSignatures.Select(sig => new {
        message_id = sig.MessageId,
        encoded_message_event_detail = sig.EncodedMessageEventDetail,
        message_event_signature = new {
            signature = sig.Signature,
            public_key_version = sig.PublicKeyVersion,
            signature_version = sig.SignatureVersion,
        },
    }),
};
var json = System.Text.Json.JsonSerializer.Serialize(keysBody);
using var content = new StringContent(json, Encoding.UTF8, "application/json");
using var resp = await http.PostAsync(
    $"https://api.x.com/2/chat/conversations/{Uri.EscapeDataString(recipientId)}/keys",
    content);
resp.EnsureSuccessStatusCode();
var data = System.Text.Json.JsonDocument.Parse(await resp.Content.ReadAsStringAsync())
    .RootElement.GetProperty("data");
string conversationId = data.GetProperty("conversation_id").GetString()!; // canonical id
byte[] convKey = prepared.ConversationKey!;
string convKeyVersion = prepared.ConversationKeyVersion;
```

--------------------------------

### SDK Configuration Methods

Source: https://docs.x.com/xchat/getting-started

Methods to configure the SDK for event decryption and verification.

```APIDOC
## set_signing_keys(entries)

### Description
Registers the public signing keys for participants to allow the SDK to verify message authorship.

## set_cache_keys(enabled)

### Description
Enables or disables the caching of signature-verified conversation keys to simplify subsequent decryption calls.
```

--------------------------------

### Set session identity and import keys

Source: https://docs.x.com/xchat/troubleshooting

Initialize the session by importing keys and setting the user identity before performing encryption or decryption operations.

```python
chat.unlock(passcode)  # or: chat.import_keys(blob)
chat.set_identity(my_user_id, signing_key_version)
```

```typescript
await chat.unlock(passcode);
chat.setIdentity(myUserId, signingKeyVersion);
```

```rust
chat.import_keys(&blob)?;
chat.set_identity(&my_user_id, &signing_key_version);
```

```go
blob, _ := chatxdk.Base64ToBytes(privateKeysB64)
_ = chat.ImportKeys(blob)
_ = chat.SetIdentity(myUserID, signingKeyVersion)
```

```csharp
chat.ImportKeys(blobBytes);
chat.SetIdentity(myUserId, signingKeyVersion);
```

```java
chat.importKeys(blobBytes);
chat.setIdentity(myUserId, signingKeyVersion);
```

--------------------------------

### Perform chat operations in Go

Source: https://docs.x.com/xchat/xchat-xdk

Demonstrates batch decryption, live event decryption, and message encryption using the Go SDK.

```go
// Batch-decrypt the backlog; senders verify against the stored keys
result, err := chat.DecryptEvents(rawEvents, nil)
for _, dm := range result.Messages {
    if dm.Event.Type == "Message" {
        fmt.Println(dm.Event.AsMessage().Text())
    }
}

// Decrypt one live event with the cached conversation key
event, err := chat.DecryptEvent(oneEventB64, nil, nil)
msg := event.AsMessage() // nil unless event.Type == "Message"

// Encrypt and sign as the session identity, under the cached key
payload, err := chat.EncryptMessage(chatxdk.EncryptMessageParams{
    ConversationID: *msg.ConversationID,
    Text:           "Hi!",
})
messageID := payload.MessageID // SDK-generated; send as message_id
_ = messageID
_ = err
```

--------------------------------

### prepare_group_create

Source: https://docs.x.com/xchat/xchat-xdk

Prepares the necessary keys and signatures for creating a new group conversation.

```APIDOC
## prepare_group_create

### Description
Prepares conversation keys for group creation. Returns two action signatures that must be included in the POST body.
```

--------------------------------

### POST /2/activity/subscriptions

Source: https://docs.x.com/xchat/real-time-events

Creates a new durable activity subscription. Requires user-context authorization.

```APIDOC
## POST /2/activity/subscriptions

### Description
Creates a new durable subscription to monitor specific user activities. Requires OAuth 2.0 user-context authorization with relevant scopes (e.g., `dm.read`).

### Method
POST

### Endpoint
/2/activity/subscriptions
```

--------------------------------

### verify_key_binding

Source: https://docs.x.com/xchat/xchat-xdk

Verifies the binding of a fetched public key before using it for encryption.

```APIDOC
## verify_key_binding

### Description
Validates the identity, signing, and signature of a fetched public key record to prevent identity substitution attacks.
```