> ## Documentation Index > Fetch the complete documentation index at: https://docs.zenzap.co/llms.txt > Use this file to discover all available pages before exploring further. # Get topic messages > Get messages from a topic with cursor-based pagination. Messages are returned in the specified order. **Authorization:** Your API key bot must be a member of the topic to access its messages. **Pagination:** Use the `cursor` parameter with the value from `nextCursor` in the response to get the next page. The `before` and `after` parameters are mutually exclusive - use one or the other, not both. **Note:** For security reasons, a 404 response is returned both when the topic does not exist and when your bot is not a member of the topic. ## OpenAPI ````yaml /openapi.yaml get /v2/topics/{topicId}/messages openapi: 3.0.3 info: title: Zenzap External Integration API description: > API for external applications to integrate with Zenzap. ## Getting Started Welcome to the Zenzap External Integration API documentation. This API is used to integrate with Zenzap. As a context we would like to familiarize you with the Zenzap platform and how it works. Zenzap is a platform for creating and managing topics and messages. Topics (Zenzap term for group chats/channels/conversations) are used to create and manage conversations with your team. Topics are used to group messages and tasks together. Messages are used to send and receive messages with your team. Tasks are used to create and manage tasks with your team. Members are used to manage your team members. API keys are used to authenticate your requests to the Zenzap API. API keys are created and managed by the Zenzap admin user. When you create a new API key, it would create a new bot user in Zenzap, on which behalf you can send messages, create topics, create tasks and manage members. All actions you perform with the API key will be performed on behalf of the bot user. The bot can be used within the scope of your organization. You can create topics, send messages, create tasks and manage members on behalf of the bot. 1. On a Zenzap admin user, go to https://app.zenzap.co/console 2. Create a new API key with the needed permissions 3. Copy the API key and secret from the API key settings 4. For each request: - Add the Authorization header with your API key - Generate a Unix timestamp in milliseconds - Calculate the HMAC-SHA256 signature: - For POST/PUT/PATCH/DELETE: Sign `{timestamp}.{body}` - For GET: Sign `{timestamp}.{uri}` (e.g., `/v2/members?limit=10`) - Add the X-Signature header with the hex-encoded signature - Add the X-Timestamp header with the timestamp used in the payload ## Authentication All API endpoints require two forms of authentication: 1. **Bearer Token**: Include your API key in the Authorization header: ``` Authorization: Bearer YOUR_API_KEY ``` 2. **Request Signing**: Include an HMAC signature and timestamp in headers: ``` X-Signature: X-Timestamp: ``` The signature includes a timestamp for replay protection. Requests older than 5 minutes are rejected. The signature payload differs by HTTP method: - **POST/PUT/PATCH/DELETE requests**: Sign `{timestamp}.{body}` - **GET requests**: Sign `{timestamp}.{uri}` The signature is calculated using HMAC-SHA256 with your API secret. **How to calculate:** 1. Get the current Unix timestamp in milliseconds 2. Determine the payload: - **POST/PUT/PATCH/DELETE**: Use `{timestamp}.{body}` (e.g., `1699564800000.{"topicId":"123"}`) - **GET**: Use `{timestamp}.{uri}` (e.g., `1699564800000./v2/members?limit=10`) 3. Calculate HMAC-SHA256 of the payload using your API secret 4. Hex-encode the result (64 character lowercase string) 5. Include timestamp in X-Timestamp header **Example (Python):** ```python import json import hmac import hashlib import time import requests def create_topic(name: str, members: list[str], description: str = None, external_id: str = None) -> dict: """Create a topic in Zenzap with HMAC signature and replay protection.""" # Build request body body = { "name": name, "members": members, } if description: body["description"] = description if external_id: body["externalId"] = external_id # Serialize body (no spaces for consistent signing) body_json = json.dumps(body, separators=(",", ":")) # Get timestamp for replay protection timestamp = int(time.time() * 1000) # Unix milliseconds # Create HMAC-SHA256 signature with timestamp signature_payload = f"{timestamp}.{body_json}" signature = hmac.new( API_SECRET.encode(), signature_payload.encode(), hashlib.sha256 ).hexdigest() # Make request headers = { "Authorization": f"Bearer {API_KEY}", "Content-Type": "application/json", "X-Signature": signature, "X-Timestamp": str(timestamp), } response = requests.post(f"{BASE_URL}/v2/topics", headers=headers, data=body_json) response.raise_for_status() return response.json() ``` **Note:** Our API documentation tools cannot automatically generate HMAC signatures. You will need to calculate this manually or use a tool like Postman with pre-request scripts. ## Rate Limits API requests are rate limited per organization. Contact support for specific limits. version: 2.0.0 contact: name: Zenzap Support url: https://zenzap.co/support servers: - url: https://api.zenzap.co description: Production server security: - bearerAuth: [] hmacSignature: [] - oauth2ClientCredentials: [] tags: - name: OAuth description: > OAuth 2.0 `client_credentials` grant. Used by API-key bots that were created with `credentialType: oauth` to mint short-lived bearer access tokens. **In a nutshell:** 1. Get a `clientId` and `clientSecret` from your bot in the Zenzap admin console. The `clientSecret` is shown once at creation; if lost, rotate it from the same screen. 2. `POST /oauth/token` with `grant_type=client_credentials` to receive a JWT access token (1-hour TTL). 3. Call any `/v2/*` endpoint with `Authorization: Bearer `. No `X-Signature` / `X-Timestamp` headers are needed on the OAuth path. 4. Re-mint when the token expires. There is **no refresh token**. Scopes are granular per endpoint — see the [Authentication page](/api-reference/authentication#oauth-scopes) for the full scope catalog and the endpoint → scope mapping. - name: Polls description: > Operations for creating polls, recording votes, and retracting votes. Polls are posted as messages in a topic. When you create a poll, each option is assigned a server-generated 6-character ID — use those IDs as `optionId` when submitting votes. **Voting constraints:** - The bot must be a member of the topic the poll was posted in - Anonymous polls (`anonymous: true`) do not support voting via the API - Votes cannot be cast on closed or expired polls - Each `{pollId, optionId, voter}` combination is idempotent - Votes can be retracted with `DELETE /v2/polls/{pollId}/votes/{voteId}` using the `id` returned when the vote was cast - name: Agentic description: > Endpoints for AI agents to programmatically set up Zenzap organizations. Use `POST /v2/agentic/organization/create` to create an organization, install a bot, and invite a human user in a single request — no authentication required. - name: Messages description: Operations for sending messages - name: Topics (group chats/channels/conversations) description: Operations for managing topics (group chats/channels/conversations) - name: Tasks description: Operations for managing tasks - name: Members description: Operations for retrieving organization members - name: Org units description: >- Operations for listing org units (teams / locations) and managing their members - name: Long Polling description: > Long polling allows your integration to fetch outbound events instead of receiving webhooks. Use `GET /v2/updates` with: - `offset`: value returned as `nextOffset` from the previous response - `limit`: max updates per request (default 50, max 100) - `timeout`: wait time in seconds when no updates are available (default 0, max 30) Event payloads in polling responses match webhook `data` payloads for the same event type. This includes `data.message.attachments[]` with signed URLs for file/image/video/audio messages. - name: Webhooks description: > Webhooks allow your application to receive real-time notifications when events occur in Zenzap. Configure your webhook URL in the Zenzap console for your API key. ## Webhook Headers Each webhook delivery includes the following headers: - `X-Zenzap-Event`: The event type (e.g., `message.created`) - `X-Zenzap-Signature`: HMAC-SHA256 signature for verification - `X-Zenzap-Timestamp`: Unix timestamp (milliseconds) when the webhook was sent - `X-Zenzap-Delivery-Id`: Unique ID for this delivery (for deduplication) ## Signature Verification Webhooks are signed using the same API secret (`BOT_SECRET`) used for request signing. Verify webhooks by calculating: ``` expected = HMAC-SHA256(BOT_SECRET, "{timestamp}.{body}") ``` Where `{timestamp}` is from `X-Zenzap-Timestamp` and `{body}` is the raw request body. If the request includes `Content-Encoding: gzip`, decompress before verifying. ## Webhook Payload Format All webhook events follow the same envelope structure (see `WebhookEvent` schema): ```json { "id": "evt_550e8400-e29b-41d4-a716-446655440099", "type": "message.created", "eventVersion": 1, "timestamp": 1699564800000, "data": { ... } } ``` The `data` field contents vary by event type. See the schemas section for detailed payload structures. ## Event Types ### Message Events | Event | Trigger | Data Schema | |-------|---------|-------------| | `message.created` | New message sent | `WebhookMessageCreatedEvent` | | `message.updated` | Message edited or transcription completed | `WebhookMessageUpdatedEvent` | | `message.deleted` | Message deleted | `WebhookMessageDeletedEvent` | ### Reaction Events | Event | Trigger | Data Schema | |-------|---------|-------------| | `reaction.added` | Emoji reaction added | `WebhookReactionAddedEvent` | | `reaction.removed` | Emoji reaction removed | `WebhookReactionRemovedEvent` | ### Member Events | Event | Trigger | Data Schema | |-------|---------|-------------| | `member.added` | User added to topic | `WebhookMemberAddedEvent` | | `member.removed` | User removed from topic | `WebhookMemberRemovedEvent` | ### Topic Events | Event | Trigger | Data Schema | |-------|---------|-------------| | `topic.updated` | Topic name/description changed | `WebhookTopicUpdatedEvent` | ## Message Types Messages can have different types based on their content: | Type | Description | Additional Fields | |------|-------------|-------------------| | `text` | Regular text message | `text` | | `image`, `file`, `video`, `audio` | Message with attachment | `attachments[]` | | `location` | Shared location | `location` | | `task` | Task snapshot | `task` | | `contact` | Shared contact | `contact` | ## Attachments & File Access Attachment URLs in webhook payloads are signed and **expire after 60 minutes**. Download files promptly after receiving the webhook. ```json { "id": "att_...", "type": "image", "name": "screenshot.png", "url": "https://storage.zenzap.co/attachments/...?token=...&expires=..." } ``` ## Voice Message Transcription Voice messages (audio attachments) are automatically transcribed: 1. **`message.created`** - Initial message with `transcription.status: "Pending"` 2. **`message.updated`** - Fired when transcription completes with `status: "Done"` ```json { "attachments": [{ "type": "audio", "name": "voice-note.mp3", "url": "https://...", "transcription": { "status": "Done", "text": "Hey team, just a quick update..." } }] } ``` ## Reply Messages Messages that reply to other messages include: - `parentId`: UUID of the message being replied to paths: /v2/topics/{topicId}/messages: get: tags: - Topics (group chats/channels/conversations) summary: Get topic messages description: > Get messages from a topic with cursor-based pagination. Messages are returned in the specified order. **Authorization:** Your API key bot must be a member of the topic to access its messages. **Pagination:** Use the `cursor` parameter with the value from `nextCursor` in the response to get the next page. The `before` and `after` parameters are mutually exclusive - use one or the other, not both. **Note:** For security reasons, a 404 response is returned both when the topic does not exist and when your bot is not a member of the topic. operationId: getTopicMessages parameters: - $ref: '#/components/parameters/XSignature' - $ref: '#/components/parameters/XTimestamp' - name: topicId in: path required: true description: The ID of the topic to get messages from schema: type: string format: uuid example: 550e8400-e29b-41d4-a716-446655440000 - name: limit in: query description: 'Maximum number of messages to return (default: 50, max: 100)' required: false schema: type: integer minimum: 1 maximum: 100 default: 50 - name: cursor in: query description: >- Opaque cursor for pagination. Use the value from `nextCursor` in the response. Cursors are cryptographically signed and validated server-side to prevent tampering. required: false schema: type: string - name: before in: query description: >- Return messages created before this timestamp (Unix milliseconds). Mutually exclusive with `after`. required: false schema: type: integer format: int64 - name: after in: query description: >- Return messages created after this timestamp (Unix milliseconds). Mutually exclusive with `before`. required: false schema: type: integer format: int64 - name: senderId in: query description: Filter messages by sender ID required: false schema: type: string - name: order in: query description: 'Sort order for messages (default: desc - newest first)' required: false schema: type: string enum: - asc - desc default: desc - name: includeSystem in: query description: 'Include system messages (default: true)' required: false schema: type: boolean default: true - name: threadId in: query description: >- Filter to messages within a specific thread (replies to a parent message) required: false schema: type: string format: uuid - name: includeReactionUsers in: query description: 'Include user IDs in reaction data (default: false, heavier payload)' required: false schema: type: boolean default: false responses: '200': description: Messages retrieved successfully content: application/json: schema: $ref: '#/components/schemas/TopicMessagesResponse' example: messages: - id: 660e8400-e29b-41d4-a716-446655440001 topicId: 550e8400-e29b-41d4-a716-446655440000 senderId: 550e8400-e29b-41d4-a716-446655440001 senderName: Alice Johnson senderType: user text: Hello team! createdAt: 1699564800000 updatedAt: 1699564800000 isEdited: false isSystem: false attachments: [] mentions: [] reactions: [] - id: 660e8400-e29b-41d4-a716-446655440002 topicId: 550e8400-e29b-41d4-a716-446655440000 senderId: b@660e8400-e29b-41d4-a716-446655440003 senderName: API Bot senderType: bot text: Task created successfully createdAt: 1699564700000 updatedAt: 1699564700000 isEdited: false isSystem: false attachments: [] mentions: [] reactions: [] nextCursor: >- eyJ0IjoxNjk5NTY0NzAwMDAwLCJpZCI6IjY2MGU4NDAwLWUyOWItNDFkNC1hNzE2LTQ0NjY1NTQ0MDAwMiIsIm8iOiJkZXNjIn0= hasMore: true '400': $ref: '#/components/responses/BadRequest' '401': $ref: '#/components/responses/Unauthorized' '404': $ref: '#/components/responses/NotFound' '500': $ref: '#/components/responses/InternalServerError' security: - bearerAuth: [] hmacSignature: [] - oauth2ClientCredentials: - message:read components: parameters: XSignature: name: X-Signature in: header required: false description: > HMAC signature of the request for authentication and replay protection. **Required only when authenticating with a static API key.** If you are using an OAuth access token (issued by `POST /oauth/token`), omit this header — the JWT carries all the authentication and integrity guarantees. **Replay Protection:** The signature includes a timestamp to prevent replay attacks. Requests with timestamps older than 5 minutes are rejected. The signature payload differs by HTTP method: - **POST/PUT/PATCH/DELETE**: HMAC-SHA256 of `{timestamp}.{body}` - **GET**: HMAC-SHA256 of `{timestamp}.{uri}` The signature is calculated as: 1. Get the current Unix timestamp in milliseconds 2. Determine the payload: - For POST/PUT/PATCH/DELETE: Use `{timestamp}.{body}` where body is the request body - For GET: Use `{timestamp}.{uri}` where uri is the full request URI (e.g., `/v2/members?limit=10`) 3. Calculate HMAC-SHA256 of the combined payload using your API secret 4. Hex-encode the output 5. Include the timestamp in the `X-Timestamp` header Example for GET request to `/v2/members?limit=10`: ``` timestamp = 1699564800000 payload = "1699564800000./v2/members?limit=10" signature = HMAC-SHA256(secret, payload) X-Signature: hex(signature) X-Timestamp: 1699564800000 ``` Example for POST request with body `{"topicId":"123","text":"Hello"}`: ``` timestamp = 1699564800000 payload = '1699564800000.{"topicId":"123","text":"Hello"}' signature = HMAC-SHA256(secret, payload) X-Signature: hex(signature) X-Timestamp: 1699564800000 ``` For `multipart/form-data` requests, sign the exact raw request body bytes (including boundaries and file bytes) as transmitted. schema: type: string pattern: ^[a-f0-9]{64}$ example: a3d5f8e7c2b1d4f6a8e9c7b5d3f1a2e4b6c8d0f2e4a6b8c0d2e4f6a8b0c2d4e6 XTimestamp: name: X-Timestamp in: header required: false description: > Unix timestamp in milliseconds when the request was created. Used for replay protection — requests older than 5 minutes are rejected. **Required only when authenticating with a static API key.** Omit when using an OAuth access token. schema: type: integer format: int64 example: 1699564800000 schemas: TopicMessagesResponse: type: object properties: messages: type: array items: $ref: '#/components/schemas/MessageItem' description: Array of message objects nextCursor: type: string description: >- Cursor for the next page. Pass this value to the `cursor` parameter to get the next page. example: >- eyJ0IjoxNjk5NTY0NzAwMDAwLCJpZCI6IjY2MGU4NDAwLWUyOWItNDFkNC1hNzE2LTQ0NjY1NTQ0MDAwMiIsIm8iOiJkZXNjIn0= hasMore: type: boolean description: Whether there are more messages to fetch example: true MessageItem: type: object properties: id: type: string format: uuid description: The message ID example: 660e8400-e29b-41d4-a716-446655440001 topicId: type: string format: uuid description: The topic ID where the message was sent example: 550e8400-e29b-41d4-a716-446655440000 senderId: type: string description: The sender's member ID example: 550e8400-e29b-41d4-a716-446655440001 senderName: type: string description: The sender's display name example: Alice Johnson senderType: type: string enum: - user - bot - system description: The type of sender example: user text: type: string description: >- The message text content. Mention tokens are preserved as `<@profileId>` (including bot profile IDs like `<@b@...>`). example: Hello team! createdAt: type: integer format: int64 description: Unix timestamp in milliseconds when the message was created example: 1699564800000 updatedAt: type: integer format: int64 description: Unix timestamp in milliseconds when the message was last updated example: 1699564800000 isEdited: type: boolean description: Whether the message has been edited example: false isSystem: type: boolean description: Whether this is a system message example: false replyCount: type: integer description: Number of replies to this message (if it's a thread parent) example: 0 attachments: type: array items: $ref: '#/components/schemas/MessageAttachment' description: Array of attachments mentions: type: array items: $ref: '#/components/schemas/MessageMention' description: Array of user mentions in the message reactions: type: array items: $ref: '#/components/schemas/MessageReaction' description: Array of reactions to the message MessageAttachment: type: object properties: id: type: string description: The attachment ID type: type: string enum: - image - file - video - audio description: The attachment type name: type: string description: The file name url: type: string description: URL to download the attachment MessageMention: type: object properties: id: type: string description: The mentioned profile ID example: 550e8400-e29b-41d4-a716-446655440001 name: type: string description: Display name used for the mention text example: Alice Johnson MessageReaction: type: object properties: emoji: type: string description: The emoji used for the reaction example: 👍 count: type: integer description: Number of users who reacted with this emoji example: 3 userIds: type: array items: type: string description: IDs of users who reacted (if includeReactionUsers is true) example: - 550e8400-e29b-41d4-a716-446655440001 responses: BadRequest: description: Bad request - invalid input content: text/plain: schema: type: string example: text is required Unauthorized: description: Unauthorized - invalid or missing API token content: text/plain: schema: type: string example: unauthorized NotFound: description: Resource not found content: text/plain: schema: type: string example: Topic not found InternalServerError: description: Internal server error content: text/plain: schema: type: string example: internal server error securitySchemes: bearerAuth: type: http scheme: bearer description: > Bearer token for the request. Two flavors: - **Static API key** — pass your API key (the value returned as `apiKey` when the bot was created). Must be paired with `X-Signature` + `X-Timestamp` (the `hmacSignature` scheme). - **OAuth access token** — pass the JWT returned by `POST /oauth/token`. No signature headers are required. hmacSignature: type: apiKey in: header name: X-Signature description: > HMAC-SHA256 signature for request verification. Required **only** when authenticating with a static API key. Omit when using an OAuth access token. oauth2ClientCredentials: type: oauth2 description: > OAuth 2.0 `client_credentials` grant for API-key bots. Use the `clientId` and `clientSecret` returned when the bot was created (or rotated) to mint short-lived access tokens. See [Authentication](/api-reference/authentication) for details. Access tokens are bearer JWTs and expire after 1 hour. There is no refresh token — re-mint with the client credentials when the token expires. flows: clientCredentials: tokenUrl: https://api.zenzap.co/oauth/token scopes: channel:list: List topics the bot belongs to channel:read: Read topic metadata channel:write: Create/update topics and manage members message:read: Read messages message:send: Send messages message:write: Edit / delete / mark-delivered / mark-read messages reaction:write: Add and remove reactions on messages task:read: Read tasks task:write: Create / update / delete tasks poll:write: Create polls and cast / retract votes member:read: List organization members updates:read: Long-poll for outbound events org_unit:read: List org units and read their members org_unit:write: Add and remove org unit members label:read: List organization labels label:write: Create organization labels ````