> ## Documentation Index > Fetch the complete documentation index at: https://help.dingtalk.io/llms.txt > Use this file to discover all available pages before exploring further. # Message types for sending and receiving > Covers the message types and data formats supported when a bot sends messages, and the data format for messages a bot receives. This topic describes the message types and data formats that bots can send, and the data formats for messages that bots receive. ## Send messages with a bot ### Message types You can send bot messages in two ways: by **calling an API** or by using a **Webhook**. The supported message types and data formats vary by method. We recommend that you send messages by calling an API. | Message type | Send via API | Send via Webhook | | ------------ | ------------ | ---------------- | | Text | ✅ | ✅ | | Markdown | ✅ | ✅ | | Image | ✅ | ❌ | | ActionCard | ✅ | ✅ | | FeedCard | ❌ | ✅ | | Link | ✅ | ✅ | | Audio | ✅ | ❌ | | File | ✅ | ❌ | | Video | ✅ | ❌ | ### Method 1: Call an API ### Important * Bot messages in one-on-one chats between a user and the bot: support **sending and receiving** images, voice messages, and files. * Bot messages in group chats: the bot can **send** images, voice messages, videos, and files. **However, users cannot @ the bot to send voice messages, videos, or files to it in a group chat.** #### Available APIs * [Send one-on-one bot messages in batches](/open/development/chatbots-send-one-on-one-chat-messages-in-batches) * [Send group chat messages with a bot](/open/development/the-robot-sends-a-group-message) #### Data format * **Message template key**: a unique identifier used when developers send messages. It allows the code to quickly reference a predefined message template. * **Message template parameters**: the actual data used to replace predefined placeholders in the message template. For example, when the message template key is `sampleText`, you need to set the value of the `content` field. * **Example**: the following HTTP example shows how an internal app bot sends a **text** message to a **group**: * Message template key: `"msgKey" : "sampleText"` * Message template parameters: `"msgParam" : "{\"content\":\"DingTalk, where progress happens\"}"` For more information, see [Send group chat messages with a bot](/open/development/the-robot-sends-a-group-message). ```http theme={"theme":{"light":"github-light","dark":"github-dark"}} POST /v1.0/robot/groupMessages/send HTTP/1.1 Host:api.dingtalk.io x-acs-dingtalk-access-token: Content-Type:application/json { "msgParam" : "{\"content\":\"DingTalk, where progress happens\"}", "msgKey" : "sampleText", "openConversationId" : "cid6KeBBLov********", "robotCode" : "dingue4kfzdxbyn*******" } ``` | Message type | Message template key | Message template parameters | Description | | ----------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | Text | sampleText | `{ "content": "xxxx" }` | | | Markdown | sampleMarkdown | `{ "title": "xxxx", "text": "xxxx" }` | | | Image | sampleImageMsg | `{ "photoURL": "xxxx" }` | **Note** photoURL can be the full URL of the image or the mediaId of the image. To obtain the value of the `media_id` parameter, call the [Upload media files](/open/development/upload-media-files) API. | | Link | sampleLink | `{ "text": "Message content test", "title": "sampleLink message test", "picUrl": "@lADOADmaWMzazQKA", "messageUrl": "http://dingtalk.io" }` | Link message. | | ActionCard | sampleActionCard | `{ "title": "Test title", "text": "Content test", "singleTitle": "View details", "singleURL": "https://open.dingtalk.com" }` | Card message with one button. | | sampleActionCard2 | `{ "title": "Message title test", "text": "Message body test", "actionTitle1": "Button 1", "actionURL1": "https://www.taobao.com", "actionTitle2": "Button 2", "actionURL2": "https://www.tmall.com" }` | Card message: two buttons arranged vertically. | | | sampleActionCard3 | `{ "title": "Message title test", "text": "Message content test", "actionTitle1": "Text of button 1", "actionURL1": "URL triggered by button 1", "actionTitle2": "Text of button 2", "actionURL2": "URL triggered by button 2", "actionTitle3": "Text of button 3", "actionURL3": "URL triggered by button 3" }` | Card message: three buttons arranged vertically. | | | sampleActionCard4 | `{ "title":"Message title test", "text":"Message content test", "actionTitle1":"Text of button 1", "actionURL1":"URL triggered by button 1", "actionTitle2":"Text of button 2", "actionURL2":"URL triggered by button 2", "actionTitle3":"Text of button 3", "actionURL3":"URL triggered by button 3", "actionTitle4":"Text of button 4", "actionURL4":"URL triggered by button 4" }` | Card message: four buttons arranged vertically. | | | sampleActionCard5 | `{ "title":"Message title test", "text":"Message content test", "actionTitle1":"Text of button 1", "actionURL1":"URL triggered by button 1", "actionTitle2":"Text of button 2", "actionURL2":"URL triggered by button 2", "actionTitle3":"Text of button 3", "actionURL3":"URL triggered by button 3", "actionTitle4":"Text of button 4", "actionURL4":"URL triggered by button 4", "actionTitle5":"Text of button 5", "actionURL5":"URL triggered by button 5" }` | Card message: five buttons arranged vertically. | | | sampleActionCard6 | `{ "title": "xxxx", "text": "xxxx", "buttonTitle1":"xxxxx", "buttonUrl1":"xxxxx", "buttonTitle2":"xxxxx", "buttonUrl2":"xxxxx" }` | Card message: two buttons arranged horizontally. | | | Audio | sampleAudio | `{ "mediaId": "@IR_P********nFkfhsisbf4A", "duration":"xxxxx" }` | Voice message: - **mediaId**: obtain the value of the `media_id` parameter by calling the [Upload media files](/open/development/upload-media-files) API. **Note** Supports OGG and AMR formats. - **duration**: duration of the voice message, in milliseconds. | | File | sampleFile | `{ "mediaId":"@lAz*********shRs5m2pRL", "fileName":"spreadsheet.xlsx", "fileType":"xlsx" }` | File message: - **mediaId**: obtain the value of the `media_id` parameter by calling the [Upload media files](/open/development/upload-media-files) API. - **fileName**: file name. - **fileType**: file type. **Note** Supported file types: xlsx, pdf, zip, rar, doc, and docx. | | Video | sampleVideo | `{ "duration":"999", "videoMediaId":"$iQEL**********AXNSs6QPPAAABhKN2L3EEzTcTB84BFM7iCAAJomlt", "videoType":"mp4", "picMediaId":"$igE**********tAFzQUABtoAIYQBpAtR3SICqrQ7ZX0nEJzAKxUDzwAAAYSjdi2cBM02vwcACAAJomltCgQ" }` | Video message: - **duration**: duration of the voice message, in seconds. - **videoMediaId**: obtain the value of the `media_id` parameter by calling the [Upload media files](/open/development/upload-media-files) API. - **videoType**: video format. Only MP4 is supported. - **picMediaId**: cover image of the video. Obtain the value of the `media_id` parameter by calling the [Upload media files](/open/development/upload-media-files) API. - **height**: display height of the video, in pixels. - **width**: display width of the video, in pixels. | #### Supported Markdown syntax > Additional notes on the Markdown syntax for the sampleMarkdown message type. ```text theme={"theme":{"light":"github-light","dark":"github-dark"}} Headings # Heading 1 ## Heading 2 ### Heading 3 #### Heading 4 ##### Heading 5 ###### Heading 6 Quote > A man who stands for nothing will fall for anything. Bold and italic **bold** *italic* Link [this is a link](http://name.com) Image Bulleted list - item1 - item2 Numbered list 1. item1 2. item2 Line break \n (add 2 spaces before and after \n) ``` ### Method 2: Use a Webhook Webhooks are supported only in group chats. For information about sending messages via a Webhook, see [Bot reply and send messages](/open/dingstart/robot-reply-and-send-messages) and [Create a custom bot](/open/dingstart/custom-bot-creation-and-installation). #### Text message ```json theme={"theme":{"light":"github-light","dark":"github-dark"}} { "at": { "atMobiles": [ "180xxxxxx" ], "atUserIds": [ "user123" ], "isAtAll": false }, "text": { "content": "I am who I am, @180xxxxxx is a different kind of spark" }, "msgtype": "text" } ``` | **Parameter** | **Required** | **Type** | **Description** | | ------------- | ------------ | -------- | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | msgtype | Yes | String | text. | | content | Yes | String | Message text. | | atMobiles | No | Array | Mobile numbers of the users to @. **Note** Add the mobile numbers of the users to @ in `content`. Only group members can be @. Mobile numbers of non-members are masked. | | atUserIds | No | Array | User IDs of the users to @. **Note** Add the user IDs of the users to @ in `content`. | | isAtAll | No | Boolean | Set to true to @ everyone; otherwise, set to false. | #### Link message This type does not support @ People. ```json theme={"theme":{"light":"github-light","dark":"github-dark"}} { "msgtype": "link", "link": { "text": "The founder calls the upcoming new version Mangrove. Before every major upgrade, product managers picked a fitting code name. Why Mangrove this time?", "title": "The train of the times rolls forward", "picUrl": "https://img.alicdn.com/tfs/TB1NwmBEL9TBuNjy1zbXXXpepXa-2400-1218.png", "messageUrl": "https://open.dingtalk.com/document/" } } ``` | **Parameter** | **Type** | Required | **Description** | | ------------- | -------- | -------- | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | msgtype | String | Yes | Message type. Set to link. | | title | String | Yes | Message title. | | text | String | Yes | Message content. Long content is truncated. | | messageUrl | String | Yes | URL to open when the message is tapped: - On mobile devices: opens in the DingTalk Client. - On PC: - Opens in the side panel by default. - To open in an external browser, see [Message link description](/open/development/message-link-description). | | picUrl | String | No | Image URL. | #### Markdown message ```json theme={"theme":{"light":"github-light","dark":"github-dark"}} { "msgtype": "markdown", "markdown": { "title":"Hangzhou Weather", "text": "#### Hangzhou Weather @150XXXXXXXX \n> 9°C, NW wind level 1, air quality good 89, relative humidity 73%\n> \n> ###### Released at 10:20 [Weather](https://www.dingalk.com) \n" }, "at": { "atMobiles": [ "150XXXXXXXX" ], "atUserIds": [ "user123" ], "isAtAll": false } } ``` | **Parameter** | **Required** | **Type** | **Description** | | ------------- | ------------ | -------- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | msgtype | Yes | String | Message type. Set to markdown. | | title | Yes | String | The content shown on the first screen of the conversation. | | text | Yes | String | Message content in Markdown format. | | atMobiles | No | Array | Mobile numbers of the users to @. **Note** Add the mobile numbers of the users to @ in `text`. Only group members can be @. Mobile numbers of non-members are masked. | | atUserIds | No | Array | User IDs of the users to @. **Note** Add the user IDs of the users to @ in `text`. | | isAtAll | No | Boolean | Set to true to @ everyone; otherwise, set to false. | Only a subset of Markdown syntax is currently supported. The supported elements are listed below: ```text theme={"theme":{"light":"github-light","dark":"github-dark"}} Headings # Heading 1 ## Heading 2 ### Heading 3 #### Heading 4 ##### Heading 5 ###### Heading 6 Quote > A man who stands for nothing will fall for anything. Bold and italic **bold** *italic* Link [this is a link](https://www.dingtalk.io/) Image Bulleted list - item1 - item2 Numbered list 1. item1 2. item2 ``` #### ActionCard message * **Whole-card jump ActionCard** ```json lines theme={"theme":{"light":"github-light","dark":"github-dark"}} { "msgtype": "actionCard", "actionCard": { "title": "Build a coffee shop", "text": " \n #### The Apple coffee shop Steve Jobs wanted to build 20 years ago \n\n Apple Store design is shifting from a tech-heavy feel to a more lifestyle-oriented one. This trend can be traced back to Apple's plan 20 years ago to open a coffee shop.", "singleTitle" : "Read more", "btnOrientation": "0", "singleURL" : "https://www.dingtalk.io/" } } ``` | **Parameter** | **Required** | **Type** | **Description** | | -------------- | ------------ | -------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | msgtype | Yes | String | Message type. Set to actionCard. | | title | Yes | String | The content shown on the first screen of the conversation. | | text | Yes | String | Message in Markdown format. **Note** To @ a user, add the user ID in `text`. For example: @manager7675 | | singleTitle | Yes | String | Title of the single button. | | singleURL | Yes | String | URL to open when the message is tapped: - On mobile devices: opens in the DingTalk Client. - On PC: - Opens in the side panel by default. - To open in an external browser, see [Message link description](/open/development/message-link-description). | | btnOrientation | No | String | Button layout: - **0**: vertical - **1**: horizontal | * **Independent-jump ActionCard** ```json lines theme={"theme":{"light":"github-light","dark":"github-dark"}} { "msgtype": "actionCard", "actionCard": { "title": "Steve Jobs wanted to build an Apple coffee shop 20 years ago — the predecessor of the Apple Store", "text": " \n\n #### The Apple coffee shop Steve Jobs wanted to build 20 years ago \n\n Apple Store design is shifting from a tech-heavy feel to a more lifestyle-oriented one. This trend can be traced back to Apple's plan 20 years ago to open a coffee shop.", "btnOrientation": "0", "btns": [ { "title": "Great content", "actionURL": "https://www.dingtalk.io/" }, { "title": "Not interested", "actionURL": "https://www.dingtalk.io/" } ] } } ``` | **Parameter** | **Required** | **Type** | **Description** | | -------------- | ------------ | -------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ | | msgtype | Yes | String | actionCard. | | title | Yes | String | The content shown on the first screen of the conversation. | | text | Yes | String | Message content in Markdown format. **Note** To @ a user, add the user ID in `text`. For example: @manager7675 | | btns | Yes | Array | Buttons. | | title | Yes | String | Button title. | | actionURL | Yes | String | URL to open when the button is tapped: - On mobile devices: opens in the DingTalk Client. - On PC: - Opens in the side panel by default. - To open in an external browser, see [Message link description](/open/development/message-link-description). | | btnOrientation | No | String | Button layout. **0**: vertical **1**: horizontal | #### FeedCard message This type does not support @ People. ```json theme={"theme":{"light":"github-light","dark":"github-dark"}} { "msgtype": "feedCard", "feedCard": { "links": [ { "title": "The train of the times rolls forward 1", "messageURL": "https://www.dingtalk.io/", "picURL": "https://img.alicdn.com/tfs/TB1NwmBEL9TBuNjy1zbXXXpepXa-2400-1218.png" }, { "title": "The train of the times rolls forward 2", "messageURL": "https://www.dingtalk.io/", "picURL": "https://img.alicdn.com/tfs/TB1NwmBEL9TBuNjy1zbXXXpepXa-2400-1218.png" } ] } } ``` | **Parameter** | **Required** | **Type** | **Description** | | ------------- | ------------ | -------- | ----------------------------------------------------------------------------------------------------------------------------------------- | | msgtype | Yes | String | feedCard. | | title | Yes | String | Text of each item. | | messageURL | Yes | String | The URL to open when an item is tapped. For more information, see [Message link description](/open/development/message-link-description). | | picURL | Yes | String | URL of the image displayed after each item. | To skip replying to the group, use the following format: ```json theme={"theme":{"light":"github-light","dark":"github-dark"}} { "msgtype": "empty" } ``` ## Receive messages with a bot When a user @ the group bot or sends a direct message to the bot, DingTalk forwards the received message to the bot callback service configured by the developer. ### Message body The following example uses the text message type. If you use HTTP callbacks, DingTalk delivers the message with a POST request. ```json theme={"theme":{"light":"github-light","dark":"github-dark"}} { "senderPlatform": "Mac", "conversationId": "cid6EUxxxxsg==", "atUsers": [ { "dingtalkId": "xxx", "staffId":"xxx", "unionId":"edxxx34" } ], "chatbotCorpId": "ding9733d095*******6cb783455b", "chatbotUserId": "$:LWCP_xxxxr5", "msgId": "msgrK2xxxxU+riw==", "senderNick": "Xiao Ding", "isAdmin": true, "senderStaffId": "0147xxxx8602", "sessionWebhookExpiredTime": 1708332604316, "createAt": 1708327204136, "senderCorpId": "ding9733d095*******6cb783455b", "conversationType": "2", "senderId": "$:LWCP_v1xxxxBv1MhAv9", "conversationTitle": "Test group", "isInAtList": true, "sessionWebhook": "https://oapi.dingtalk.io/robot/sendBySession?session=66d7c695a9xxxxdeb885", "text": { "content": " text" }, "robotCode": "dingoxxxxdm3k", "msgtype": "text" } ``` | **Parameter** | **Type** | **Description** | | ------------------------- | --------------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | senderPlatform | String | The platform from which the message is sent. | | conversationId | String | Chat ID. | | atUsers | Array of Object | Information about the @ users. - **dingtalkId**: encrypted ID of the @ user. - **staffId**: user ID of the @ user. This field is empty for external users in an External Chat. - **unionId**: unionId of the @ user. | | chatbotCorpId | String | Encrypted organization ID of the organization to which the bot belongs. | | chatbotUserId | String | Encrypted bot ID. | | msgId | String | Encrypted message ID. | | senderNick | String | Name of the sender. | | isAdmin | Boolean | Whether the sender is an Admin: - true: yes - false: no Takes effect after the bot is published. Otherwise, this field is not returned. | | senderStaffId | String | The user ID of the member who @ the bot in an internal group. If the sender is not a member of the organization to which the bot belongs (for example, an external user @ the bot in an external group), this field is empty. Takes effect after the bot is published. Otherwise, this field is not returned. | | senderUnionId | String | unionId of the sender. | | sessionWebhookExpiredTime | Long | Expiration time of the Webhook URL for the current conversation. | | createAt | String | Message timestamp, in milliseconds. | | senderCorpId | String | Organization ID of the sender in an internal group. | | conversationType | String | Conversation type: - **1**: Direct Message - **2**: Group Chat | | senderId | String | Encrypted sender ID. | | conversationTitle | String | The title of the conversation. Available only in group chats. | | isInAtList | Boolean | Whether the bot is in the @ list. | | sessionWebhook | String | Webhook URL for the current conversation. | | text | Object | Message text: - content: the message content received by the bot. This field exists only when the message type is text. | | msgtype | String | Message type: - text: text message - richText: Rich Text message - picture: image message - audio: voice message - video: video message - file: file message For the specific format of each type, see **Message types** below. | | robotCode | String | Bot code. Custom bots do not have a robotCode. | ### Message types Bots can currently receive messages of the following types: text, voice, image, file, video, and Rich Text. The fields for each message type are explained below. Other than the message type and message body fields, the parameters are the same as in the table above. #### Text message ```json theme={"theme":{"light":"github-light","dark":"github-dark"}} { "msgtype": "text", "text": { "content": "Hello" } } ``` | **Parameter** | **Type** | **Description** | | ------------- | -------- | ----------------------------------------------------------------------- | | msgtype | String | Message type: - **text**: text message | | text | Object | Message text: - **content**: the message content received by the bot. | #### Rich Text message ```json theme={"theme":{"light":"github-light","dark":"github-dark"}} { "msgtype": "richText", "content": { "richText": [ { "text": "Hello" }, { "downloadCode": "mIofN681YE3f*************JkVBG2vhj4Q9、d2tn/t6XxjaB6UxxxxOVnYYbn1aMT/n3JFgb4i64X3TFxxxxGWxJPR/egKS8syvGzxxxxOO/FYLor2Q==", "type": "picture" } ] } } ``` | Name | Type | Description | | -------- | --------------- | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | msgtype | String | Message type: - **richText**: Rich Text | | content | Object | Message content. | | richText | Array of Object | Rich Text list. **Note** The message list can contain: - **text**: text message - **picture**: image message Use the image downloadCode to obtain a temporary download URL by calling the Server API [Download the file content of messages received by the bot](/open/development/download-the-file-content-of-the-robot-receiving-message). | #### Image message ```json theme={"theme":{"light":"github-light","dark":"github-dark"}} { "msgtype": "picture", "content": { "downloadCode": "mIofN681YE3f/+m+**********8rs4RGdQAwyVs3B75N7boKf8ep0FBB122u9YY/novFAM9BQrirm4/+avZaCV+6nnZ0Zk=" } } ``` | **Parameter** | **Type** | **Description** | | ------------- | -------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | msgtype | String | Message type: - **picture**: image message | | downloadCode | String | Download code of the image file, used to retrieve the binary content of the image. Call the Server API [Download the file content of messages received by the bot](/open/development/download-the-file-content-of-the-robot-receiving-message) to obtain a temporary download URL. | #### Voice message In Group Chat conversations, the bot **does not support** receiving voice messages when a Group member @ the bot. ```json theme={"theme":{"light":"github-light","dark":"github-dark"}} { "msgtype": "audio", "content": { "duration": 4000, "downloadCode": "mIofN681YE3f/+m+Nn***********geqPd7xpJF/9NbOAORDnadz0WbSwWTiYvByBeYDjbg2ecUdno/RGtZ/sqzdvoh00EWw1U6xNqLC3Bk51U+i", "recognition": "DingTalk, where progress happens" } } ``` | **Parameter** | **Type** | **Description** | | ------------- | -------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ | | msgtype | String | Message type: - **audio**: voice message | | downloadCode | String | Download code of the voice file, used to retrieve the binary content of the voice message. Call the Server API [Download the file content of messages received by the bot](/open/development/download-the-file-content-of-the-robot-receiving-message) to obtain a temporary download URL. | | recognition | String | Text from Speech-to-Text recognition. | | duration | Long | Duration of the voice message, in milliseconds. | #### Video message In Group Chat conversations, the bot **does not support** receiving video messages when a Group member @ the bot. ```json theme={"theme":{"light":"github-light","dark":"github-dark"}} { "msgtype": "video", "content": { "duration": 4000, "downloadCode": "mIofN681YE3f/****************OAORDnadz0WbSwWTiYvByBeYDjbg2ecUdno/RGtZxxxxLC3Bk51U+i", "videoType": "mp4" } } ``` | **Parameter** | **Type** | **Description** | | ------------- | -------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | msgtype | String | Message type: - **video**: video message | | downloadCode | String | Download code of the video file, used to retrieve the binary content of the video. Call the Server API [Download the file content of messages received by the bot](/open/development/download-the-file-content-of-the-robot-receiving-message) to obtain a temporary download URL. | | videoType | String | Video file type. | | duration | Long | Duration of the video, in milliseconds. | #### File message In Group Chat conversations, the bot **does not support** receiving file messages when a Group member @ the bot. ```json theme={"theme":{"light":"github-light","dark":"github-dark"}} { "msgtype": "file", "content": { "downloadCode": "mIofN681YE3f*************pJF/9NbOAORDnadxxxxg2ecUdno/RGtZ/sqzdxxxxC3Bk51U+i", "fileName": "DingTalk progress happens.pdf" } } ``` | **Parameter** | **Type** | **Description** | | ------------- | -------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | msgtype | String | Message type: - **video**: file message | | downloadCode | String | Download code of the file, used to retrieve the binary content of the file. Call the Server API [Download the file content of messages received by the bot](/open/development/download-the-file-content-of-the-robot-receiving-message) to obtain a temporary download URL. | | fileName | String | File name. | ### Related content If you select HTTP mode as the message receiving mode when [creating an internal app bot](/open/dingstart/configure-the-robot-application), the HTTP header parameters shown below are included along with the message body when the bot receives a message: ```json theme={"theme":{"light":"github-light","dark":"github-dark"}} { "Content-Type": "application/json; charset=utf-8", "timestamp": "1577262236757", "sign":"xxxxxxxxxx" } ``` | **Parameter** | **Description** | | ------------- | ----------------------------------------------------- | | timestamp | Timestamp when the message was sent, in milliseconds. | | sign | Signature value. | You must verify the timestamp and sign in the header to confirm that the request is a legitimate request from DingTalk and to prevent third parties from impersonating DingTalk to call your HTTPS service. The verification rules are as follows: * If the difference between the timestamp and the current system timestamp is greater than 1 hour, the request is considered illegitimate. * If the sign does not match the signature value you calculate, the request is considered illegitimate. A request is considered legitimate only when both the timestamp and sign pass verification. Use the HmacSHA256 algorithm to calculate the signature, and then encode it with Base64 to get the final signature value. Example: ```java theme={"theme":{"light":"github-light","dark":"github-dark"}} import javax.crypto.Mac; import javax.crypto.spec.SecretKeySpec; import org.apache.commons.codec.binary.Base64; public class Test { public static void main(String[] args) throws Exception { Long timestamp = 1577262236757L; String appSecret = "this is a secret"; String stringToSign = timestamp + "\n" + appSecret; Mac mac = Mac.getInstance("HmacSHA256"); mac.init(new SecretKeySpec(appSecret.getBytes("UTF-8"), "HmacSHA256")); byte[] signData = mac.doFinal(stringToSign.getBytes("UTF-8")); String sign = new String(Base64.encodeBase64(signData)); System.out.println(sign); } } ``` | **Configuration item** | **Description** | | ---------------------- | ------------------------------------------------------------------------------------------------------------- | | timestamp | Current timestamp, in milliseconds. | | appSecret | The Client Secret of the app. For more information, see [Client Secret](/open/dingstart/basic-concepts-beta). | ### Error codes When the bot Webhook or Stream usage exceeds the quota, the following behavior occurs: #### Error behavior ##### Group Chat conversations ##### Direct Message conversations #### Error description | Error code (errorCode) | Error message (errorMessage) | **Description** | Solution | | ---------------------- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------ | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ | | 20001 | Due to excessive call volume, your message service is currently paused. Contact your organization Admin for assistance. An **errorMessage** field is added to the received message to display the error message. | - The `text` and `content` fields are not included in the received message. - Sign in to the [Developer Console](https://open-dev.dingtalk.io/) to view the call volume. | Upgrade to DingTalk Professional Edition or purchase an add-on package. For more information, see [Organization add-on package purchase instructions](https://open.dingtalk.com/document/orgapp/purchase-instructions-for-enterprise-additional-purchase-package). | ### Related documents * Send group chat messages with an Enterprise bot * Send one-on-one messages with an Enterprise bot * Send group chat messages with a Custom bot * Send group chat messages with a group template bot