Overview

With Sendbird's Chat Platform API, you can build messaging functionalities ranging from the essential to the advanced, including features such as message threading, delivery receipts, and emoji reactions.

Message types

There are three types of messages in Sendbird Chat.

Text: A message containing a string of text. The message must be sent by a user and, in the case of group channels, the user must be a member of the channel to be able to send the message.
File: A message containing a file, which can be directly uploaded to the Sendbird server or specified by its URL. The message must be sent by a user and, in the case of group channels, the user must be a member of the channel to be able to send the message. The maximum file size is 25MB.
Multiple files: A message containing more than two files, which can be directly uploaded to the Sendbird server or specified by their URL. These messages are supported only in group channels and, just like a regular file message, the sender must be a member of the channel. The maximum number of file attachments is 30 and the default maximum size per file is set to 25MB. To adjust the numbers, contact our Sales team.
Admin: A system message sent without a sender and, in the case of group channels, without the sender needing to be a member of the channel. Common use cases include general notices to a channel like "Livestream will begin in 1 minute! Your messages may be monitored to ensure a safe, welcoming environment." and auto event messages like "User 1 joined the channel."

Comparing message types

Characteristics and supported features of each message type are shown below.

	Text	File	Admin
Representative value	`MESG`	`FILE`	`ADMM`
Content	Text only	File only	Text only
Send by user	Required	Required	Not required
Join group channel	Required	Required	Not required
Announcements	Supported	N/A	Supported
Delivery receipts	Supported	Supported	N/A
Message search	Supported	Supported	N/A
Message threading	Supported	Supported	N/A
Migration	Supported	Supported	Supported
Polls	Supported * Except scheduled message	N/A	N/A
Reactions	Supported	Supported	N/A
Read receipts	Supported	Supported	Supported
Translations	Supported	N/A	N/A

Resource representation

The following tables show the lists of properties in a message resource for a text message, file message, and admin message.

List of properties for a text message

Property name	Type	Description
message_id	long	The unique ID of the message.
type	string	The type of the message. The value is `MESG` for a text message.
custom_type	string	The custom message type used for message grouping. The length is limited to 128 characters. * Custom types are also used to segment metrics within Sendbird's Advanced analytics, which enables the sub-classification of data views.
channel_url	string	The unique URL of the channel where the message is sent to.
user	nested object	The user who sent the message. * This isn't updated in real-time, but it's a snapshot of the user object when a message object is created.
mention_type	string	The mention type that indicates whether to call the attention of specific users or all users in the channel. The value of `users` indicates that up to ten users in `mentioned_user_ids` are notified of the mention, while the value of `channel` indicates that up to ten users in the channel are notified of the mention.
mentioned_users[]	array of objects	An array of users mentioned in the message.
is_removed	boolean	Indicates whether the message is removed from the channel.
message	string	The content of the message.
translations	object	The messages translated from the original language into one or more specified languages.
data	string	Additional message information such as custom font size or font type in JSON or other formats. More details on what can be stored in this field are available here.
sorted_metaarray	array of objects	An array of JSON objects consisting of key-values items to store additional message information which can be used for classification and filtering. When retrieving, items are returned in the order they were added. More details on what can be stored in this field are available here.
message_events	nested object	A set of events configured for each instance a message is sent or updated. * The events in this object are only supported in group channels.
message_events.send_push_notification	string	Indicates which group of users to send push notifications to. Acceptable values are the following. - `none`: No push notifications are sent. - `receivers`: Push notifications are only sent to the intended recipients. - `sender`: A push notification is only sent to the sender. - `all`: Push notifications are sent to both the intended receivers and the sender.
message_events.update_unread_count	boolean	Indicates whether to update `unread_count` for users in the channel. The `update_mention_count` property inside `message_events` inherits the value of `update_unread_count`.
message_events.update_last_message	boolean	Indicates whether to update the `last_message` property of the channel if the updated message is the last message of the channel.
og_tag	nested object	The Open Graph (OG) metadata contained in the given URL when a text message or an admin message includes the URL of a web page. This consists of properties such as `og:url`, `og:title`, `og:description`, and `og:image`.
created_at	long	The time when the message was sent in Unix milliseconds format.
updated_at	long	The time when the message was updated in Unix milliseconds format.
file	nested object	The file contained in the message. This property is empty for any text messages.
is_apple_critical_alert	boolean	Indicates whether the message is a critical alert.
thread_info	nested object	The thread information consisting of the `reply count`, `most_replies`, `last_replied_at`, and `updated_at` properties. The `thread_info` property is only retrieved if the message is a parent message.
thread_info.reply_count	long	The total number of replies in the thread. The value of `0` indicates that there is no reply.
thread_info.most_replies	array of objects	An array of one or more `JSON` objects containing the information of one or more users who replied the most. Up to five objects can be returned.
thread_info.last_replied_at	long	The time when the last reply was added in Unix milliseconds format. The value of `0` indicates that there is no reply.
thread_info.updated_at	long	The time when the thread information was updated due to a deleted or newly added reply in the thread, in Unix milliseconds format.
parent_message_id	long	The unique ID of a thread's parent message. This property is only retrieved if the message is a reply.
parent_message_info	nested object	The information of the thread's parent message including the text, user information, and message type. This property is only retrieved if the message is a reply.
is_reply_to_channel	boolean	Indicates whether the message was sent as a reply to the channel.
~~root_message_id~~	long	*(Deprecated)* Reserved value. This must be the same as `parent_message_id`.
~~parent_message_text~~	string	*(Deprecated)* The text of a thread's parent message. If the `include_parent_message_text` parameter is set to `true`, the value of this property is retrieved in the response.

List of properties for a file message

Property name	Type	Description
message_id	long	The unique ID of the message.
type	string	The type of the message. The value is `FILE` for a file message.
custom_type	string	The custom message type used for message grouping. The length is limited to 128 characters. * Custom types are also used to segment metrics within Sendbird's Advanced analytics, which enables the sub-classification of data views.
channel_url	string	The unique URL of the channel where the message is sent to.
user	nested object	The user who sent the message. * This isn't updated in real-time, but it's a snapshot of the user object when a message object is created.
mention_type	string	The mention type that indicates whether to call the attention of specific users or all users in the channel. The value of `users` indicates that up to ten users in `mentioned_user_ids` are notified of the mention, while the value of `channel` indicates that up to ten users in the channel are notified of the mention.
mentioned_users[]	array of objects	An array of users mentioned in the message.
is_removed	boolean	Indicates whether the message is removed from the channel.
file	nested object	The information of a file in the file message, which was either directly uploaded to Sendbird server or specified by an externally hosted URL. In the context of a multiple file message, the `file` field contains information of the first file among all attached files.
files	nested object	The information on the rest of the files in the multiple file message, which were either directly uploaded to the Sendbird server or specified by an externally hosted URL. It has properties like `url`, `file_name`, `file_size`, `file_type`, and `thumbnails`.
file.url	string	The URL of the file where it is hosted.
file.name	string	The name of the file that you can specify.
file.type	string	The MIME type of the file that you can specify.
file.size	int	The size of the file that you can specify.
file.data	string	The string data which can contain additional message information such as custom font size, font type, or a JSON-formatted string.
sorted_metaarray	array of objects	An array of one or more JSON objects consisting of key-value items to store additional message information. When retrieving, items are returned in the order they were added.
thumbnails[]	array of objects	An array of thumbnail images that were either automatically generated by Sendbird server from the uploaded image or video file in the message or specified by externally hosted URLs.
require_auth	boolean	Indicates whether to require an authentication key to verify if the file is being properly accessed. Only the user who uploaded the file or users who are in the channel where the file was uploaded should have access. The authentication key managed internally by the Sendbird system is generated every time a user logs in to the Sendbird server and is valid for three days starting from the last login. If set to `false`, Sendbird tries to access a file without any key. To access encrypted files, such as the files in the Sendbird server which are by default encrypted, the property must be set to `true`. (Default: `false`)
message_events	nested object	A set of events configured for each instance a message is sent or updated. * The events in this object are only supported in group channels.
message_events.send_push_notification	string	Indicates which group of users to send push notifications to. Acceptable values are the following. - `none`: No push notifications are sent. - `receivers`: Push notifications are only sent to the intended recipients. - `sender`: A push notification is only sent to the sender. - `all`: Push notifications are sent to both the intended receivers and the sender.
message_events.update_unread_count	boolean	Indicates whether to update `unread_count` for users in the channel. The `update_mention_count` property inside `message_events` inherits the value of `update_unread_count`.
message_events.update_last_message	boolean	Indicates whether to update the `last_message` property of the channel if the updated message is the last message of the channel.
created_at	long	The time when the message was sent in Unix milliseconds format.
updated_at	long	The time when the message was updated in Unix milliseconds format.
thread_info	nested object	The thread information consisting of the `reply count`, `most_replies`, `last_replied_at`, and `updated_at` properties. The `thread_info` property is only retrieved if the message is a parent message.
thread_info.reply_count	long	The total number of replies in the thread. The value of `0` indicates that there is no reply.
thread_info.most_replies	array of objects	An array of one or more JSON objects containing the information of one or more users who replied the most. Up to five objects can be returned.
thread_info.last_replied_at	long	The time when the last reply was added in Unix milliseconds format. The value of `0` indicates that there is no reply.
thread_info.updated_at	long	The time when the thread information was updated due to a deleted or newly added reply in the thread, in Unix milliseconds format.
parent_message_id	long	The unique ID of a thread's parent message. This property is only retrieved if the message is a reply.
parent_message_info	nested object	The information of the thread's parent message including the text, user information, and message type. This property is only retrieved if the message is a reply.
is_reply_to_channel	boolean	Indicates whether the message was sent as a reply to the channel.
~~parent_message_text~~	string	*(Deprecated)* The text of a thread's parent message. If the `include_parent_message_text` parameter is set to `true`, the value of this property is retrieved in the response.

List of properties for an admin message

Property name	Type	Description
message_id	long	The unique ID of the message.
type	string	The type of the message. The value is `ADMM` for an admin message.
custom_type	string	The custom message type used for message grouping. The length is limited to 128 characters. * Custom types are also used to segment metrics within Sendbird's Advanced analytics, which enables the sub-classification of data views.
channel_url	string	The unique URL of the channel where the message is sent to.
mention_type	string	The mention type that indicates whether to call the attention of specific users or all users in the channel. The value of `users` indicates that up to ten users in `mentioned_user_ids` are notified of the mention, while the value of `channel` indicates that up to ten users in the channel are notified of the mention.
mentioned_users[]	array of objects	An array of users mentioned in the message.
is_removed	boolean	Indicates whether the message is removed from the channel.
message	string	The content of the message.
data	string	A string data which can contain additional message information such as custom font size, font type, or a JSON-formatted string.
sorted_metaarray	array of objects	An array of one or more JSON objects consisting of key-value items to store additional message information. When retrieving, items are returned in the order they were added.
message_events	nested object	A set of events configured for each instance a message is sent or updated. * The events in this object are only supported in group channels.
message_events.send_push_notification	string	Indicates which group of users to send push notifications to. Acceptable values are the following. - `none`: No push notifications are sent. - `receivers`: Push notifications are only sent to the intended recipients. - `sender`: A push notification is only sent to the sender. - `all`: Push notifications are sent to both the intended receivers and the sender.
message_events.update_unread_count	boolean	Indicates whether to update `unread_count` for users in the channel. The `update_mention_count` property inside `message_events` inherits the value of `update_unread_count`.
message_events.update_last_message	boolean	Indicates whether to update the `last_message` property of the channel if the updated message is the last message of the channel.
og_tag	nested object	The Open Graph (OG) metadata contained in the given URL when a text message or an admin message includes the URL of a web page. This consists of properties such as `og:url`, `og:title`, `og:description`, and `og:image`.
created_at	long	The time when the message was sent in Unix milliseconds format.
updated_at	long	The time when the message was updated in Unix milliseconds format.

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Message types Resource representation