Group System Overview

The group system is an instant messaging system that allows multiple participants to communicate in one chat. The group system has the following basic capabilities:

• Comprehensive group management capabilities: group creation and disbanding, member management, group profile management, member profile management, and more.
• Stable and reliable messaging and a sophisticated group message management mechanism: permission control, muting, vulgar language filtering, message callback, message roaming, and more.
• Based on common use cases, the following group types are configured by default: work group (Work), public group (Public), meeting group (Meeting), and audio-video group (AVChatRoom). You can create custom group types based on your business needs.
• Upper limit on the number of group members:
  • The number of members in a non-audio-video group can be increased to a maximum of 6,000 if fees are paid. For more information, see Pricing.
    There is no upper limit on the number of members in an audio-video group (AVChatRoom).
• On the web or mini program end, audio-video groups allow users to receive messages as guests without logging in.

Note：

• Although audio-video groups (AVChatRoom) support unlimited group members, if a spike in group members is expected within a short time (in scenarios such as large online events where the number of members in a single group reaches 50,000 or above), contact sales representatives in advance and report service resource usage by providing the SDKAppID and the scheduled event time.
• Currently, historical message storage is available only for non-audio-video groups, with messages stored for 7 days for billing plans of the Trial Edition and Pro Edition and 30 days for the Ultimate Edition by default. If you require a longer storage period, change the storage period of historical messages in the console. Increasing the storage period of historical messages is a value-added service. For more information on pricing, see Pricing.

IM's group system is highly customizable, allowing you to use:

• Custom message formats
• Custom group IDs
• Custom fields
• Custom group types
• Custom callbacks

Group Member Roles

The following table lists various group member roles and their permissions:

Group Member Role	Description	Management Permission
Ordinary member	An ordinary member has no management permissions.	In a work group (Work), an ordinary member has the permission to modify the group profile.
Admin	An admin is appointed by the group owner to assist in managing group members and holds certain management permissions.	Modify the group profile Remove an ordinary member from the group Mute an ordinary member, that is, prevent the ordinary member from speaking for a certain period of time Approve or reject a membership application Work groups do not support the setting of admins by default.
Group owner	A group owner is the creator of a group and has the highest level of management permissions in the group.	The group owner has the following permissions in addition to all permissions held by an admin: Appoint or cancel an admin Remove an admin from the group Mute an admin Disband the group Transfer the group
App admin	This special role has the authority to manage all group permissions in the app and has more power than the group owner.	The app admin has the same permissions as the group owner, whether it is a member of the group or not.

Group Types

Based on common use cases, IM provides the following default group types:

Group Type	Applicable Scenario
Work group (Work)	A work group is similar to an ordinary WeChat group. After a work group is created, only a group member can invite other users to join this group, and the invitation does not need to be approved by the invited user or group owner.
Public group (Public)	A public group is similar to a QQ group. After a public group is created, the group owner can specify a group admin. After a public group is created, the group owner can designate group admins. To join the group, a user needs to search for the group ID and send an application, and the application needs to be approved by the group owner or an admin before the user can join the group.
Meeting group (Meeting)	After a meeting group is created, a user can join and quit the group as desired, and view messages sent before the user joined the group. This group type is suitable for scenarios where Tencent Real-Time Communication (TRTC) is used, for example, audio and video conferencing and online education.
Audio-video group (AVChatRoom)	After an audio-video group is created, a user can join and quit the group as desired. This group type does not limit the number of members, but it does not support storage of historical messages. It can be used together with Live Video Broadcasting (LVB) to support on-screen comments.

Differences in basic group capabilities

Item	Work Group	Public Group	Meeting Group	Audio-Video Group
Available member roles	Group owner Ordinary member App admin	Group owner Admin Ordinary member App admin	Group owner Admin Ordinary member App admin	Group owner Ordinary member App admin
Who can modify the group profile	Ordinary member	Group admin Group owner App admin	Group owner App admin	App admin
Number of group members whose information can be obtained	All group members	All group members	All group members	Up to 300 group members
Who can disband a group	App admin	Group owner and app admin	Group owner and app admin	App admin

Note：

• Ordinary members of a work group (Work) can modify only the group name, introduction, announcement, and group profile photo URL, but not other group profile information.
• If the roles of a group type cannot meet your business needs, you can add roles by setting member-level custom fields.
• It is necessary to obtain the information about some members in scenarios where an audio-video group displays a list of some of its members.

Differences in joining a group

Item	Work Group	Public Group	Meeting Group	Audio-Video Group
Perform an exact search for a group ID to join a group	Not supported	Supported	Supported	Supported
Perform a fuzzy search for group information to join a group	Not supported	Not supported	Not supported	Not supported
Apply to join a group	Not supported	Supported. Approval from the group owner or admin is needed.	Supported. No approval is needed.	Supported. No approval is needed.
Join a group after receiving an invitation from a group member	Supported	Not supported	Not supported	Not supported

Note：

• Exact search is to search for a group by group ID. Fuzzy search is to search for a group by fields such as the group name.
• Approval for joining a group: the group owner and admin can choose to approve or reject applications made by non-members to join the group. Only approved users can join the group.
• For a group type that does not support the invitation of non-members to a group, group members can share the group ID with non-members in the app so that the non-members can join the group.

Differences in member management capabilities

Item	Work Group	Public Group	Meeting Group	Audio-Video Group
Set an admin	Not supported	Supported	Supported	Not supported
A group owner quits the group	Supported. After the group owner quits, the group has no group owner.	Not supported	Not supported	Not supported
Remove a group member	Supported. The group owner can remove group members.	Supported. The group owner and admin can remove group members, but the admin can remove only ordinary group members.	Supported. The group owner and admin can remove group members, but the admin can remove only ordinary group members.	Not supported. The muting feature can be used to achieve a similar effect.
Mute a group member	Not supported	Supported. The group owner and admin can mute group members, but the admin can mute only ordinary group members.	Supported. The group owner and admin can mute group members, but the admin can mute only ordinary group members.	Supported. The group owner can mute group members.
Periodically remove offline group members	Supported, but disabled by default	Supported, but disabled by default	Supported, but disabled by default	Not supported

Note：

Muted group members cannot send group chat messages within the mute period.

Differences in group limits

Item	Work Group/Public Group/Meeting Group	Audio-Video Group
Maximum number of members	Trial Edition: 20 per group Pro Edition: 200 per group by default, can be increased to 2,000 per group via value-added service Flagship Edition: 2,000 per group, can be increased to 6,000 per group via value-added service	Unlimited
Maximum number of groups	Trial Edition: up to 100 existing groups, and disbanded groups do not count against the quota Pro Edition or Ultimate Edition: unlimited	Trial Edition: up to 10 existing groups, and disbanded groups do not count against the quota Pro Edition: up to 50 existing groups, and disbanded groups do not count against the quota. You can upgrade to an unlimited number of audio-video groups by purchasing a value-added service. Ultimate Edition: unlimited

Note：

• For an SDKAppID of the Pro Edition or Ultimate Edition, up to 10,000 groups (the number of created groups minus the number of disbanded groups) can be added in a day regardless of the group type.
• In the Pro Edition or Flagship Edition SDKAppID, free peak group count is 100,000 per month, and you will need to pay for usage exceeding the free quota. We recommend you delete groups that are no longer needed.

Differences in message capabilities

Item	Work Group	Public Group	Meeting Group	Audio-Video Group
Unread message count	Supported	Supported	Not supported	Not supported
Group members can view messages sent before they join the group	Not supported	Not supported	Supported	Not supported
Historical message storage	Supported	Supported	Supported	Not supported
Member change notifications	Supported	Supported	Not supported	Supported
A message must be sent to activate a new group	Required	Not required	Not required	Not required
Default message receiving option	Receive online and offline pushed messages	Receive online and offline pushed messages	Receive only online pushed messages	Receive only online pushed messages
Users can receive group messages as guests without logging in	Not supported	Not supported	Not supported	Supported

Note：

• For a group that requires activation, before the group owner sends a message, the group is inactive and invisible to all group members except the group owner. A group that does not require activation is visible to all group members once it is created.
• Currently, offline push is available only on Android (Android offline push) and iOS (APNs push) platforms.
• The work group, public group, and meeting group have the historical message storage capability, which allows historical messages to be stored for 7 days (30 days for the Ultimate Edition) free of charge by default. If you need a longer storage period, change the storage period of historical messages in the console. Increasing the storage period of historical messages is a value-added service. For more information on pricing, see Pricing.

Differences in batch import and automatic repossession

Item	Work Group/Public Group/Meeting Group	Audio-Video Group
Importing groups, group members, and group messages is allowed	Yes. It is allowed when historical groups are migrated from a third-party platform to IM.	No. Only existing groups, group members, and group messages can be used.
Time before a group is automatically repossessed (in seconds)	The backend does not repossess groups, unless the group owner disbands the group or all members quit the group.	The backend does not repossess groups, unless the group owner disbands the group or all members quit the group.

Note：

If you need to enable the group repossession feature, you can submit a ticket for application according to the ticket template. After configuration, inactive groups (where no members speak and change) will be cleaned up based on the group type.

Group Data Structure

Group basic information

Field Name	Type	Description	Remarks
GroupId	String	Unique identifier of the group	Read-only. Each group ID must be unique in the app. The prefix is @TGS#, and custom group IDs can also be used in the app.
Type	String	Group type	Read-only. The following group types are supported by default: work group, public group, meeting group, and audio-video group. For more information, see Group Types. In the SDK of an earlier version, group types also include the private group, ChatRoom, and BChatRoom, which are not recommended.
Name	String	Name of the group	Readable and writable. The maximum length is 30 bytes and cannot be adjusted.
Introduction	String	Introduction of the group	Readable and writable. The maximum length is 240 bytes and cannot be adjusted.
Notification	String	Group announcement	Readable and writable. The maximum length is 300 bytes and cannot be adjusted.
FaceUrl	String	URL of the group's profile photo	Readable and writable. The maximum length is 100 bytes and cannot be adjusted.
Owner_Account	String	ID of the group owner	Read-only.
CreateTime	Integer	Creation time of the group	Read-only.
InfoSeq	Integer	This value increases every time the group information changes.	Read-only.
LastInfoTime	Integer	Time of the last change to group information	Read-only.
LastMsgTime	Integer	Time of the last message in the group chat	Read-only.
NextMsgSeq	Integer	Sequence number of the next message in the group chat	Read-only. Every message in the group chat has a unique sequence number. Sequence numbers are consecutive numbers based on the sequence of sent messages. With every message sent in the group chat, NextMsgSeq (starting from 1) increases by 1.
MemberNum	Integer	Number of current members	Read-only.
MaxMemberNum	Integer	Maximum number of members	Default value: the upper limit of the paid plan; for example, it is 20 on Trial Edition. If you upgrade the plan, you need to modify this field to the corresponding value according to the basic information of the modified group
ApplyJoinOption	String	Membership application option	The following options are available: DisableApply: disallow any application. NeedPermission: group owner or admin's approval is required. FreeAccess: users can join the group freely without prior approval.

Note：

The permissions to modify the group name, introduction, announcement, and profile photo URL are described as follows:

• In a work group, any member can modify them.
• For other group types, only non-ordinary members can modify them.

Group member profile

Field Name	Type	Description	Remarks
Member_Account	String	Group member ID	Read-only.
Role	String	Role in the group	A group has the following roles: Owner (group owner), Admin (group admin), and Member (group member).
JoinTime	Integer	Time of joining the group	Read-only.
MsgSeq	Integer	Sequence number of the current read message of the member	Read-only.
MsgFlag	String	Message receiving option	The following options are available: AcceptAndNotify: receive and notify. AcceptNotNotify: receive without notifying (remote APNs push is not triggered) Discard: block group messages (messages are not pushed to clients)
LastSendMsgTime	Integer	Time of sending the last message	Supported by work groups, public groups, and meeting groups, but not audio-video groups.
NameCard	String	Group name card	Readable and writable.

Custom Group Types

If the group types provided by IM cannot meet your needs, you can prepare relevant information according to the ticket template and submit a ticket to apply to modify existing group types or add custom group types.
For example, you can create a group that is used in an office environment. This group is similar to a work group, but every member has the highest level of management permissions and can view messages sent before they join the group. In this case, you can:

• Choose the work group type and submit a ticket to apply to enable the view historical messages before joining and allow ordinary members to remove members options.
• Submit a ticket to apply for a new group type named OAGroup. Specify work group as the reference type and enable the view historical messages before joining and allow ordinary members to remove members options.

Note：

• When creating a group type, you must specify a group type as a reference type. Note that BChatRoom in SDK of earlier versions cannot be specified as a reference type.
• After configuration, the new group type will have new features that are specified in the ticket, and the same features as the reference type.

Custom Group IDs

When a group is created in the app, IM assigns a default group ID to the new group by default. This default group ID starts with @TGS# and is unique in the app.
IM also allows you to customize group IDs that are simple and easy to remember and communicate. A custom group ID must be a string of ASCII characters (0x20-0x7e) with a length less than 48 bytes. Do not use @TGS# as the prefix to avoid confusion with assigned group IDs.

Custom Fields

IM allows you to configure up to 10 group-level custom fields and 5 member-level custom fields based on your business needs. With custom fields, apps can attach additional data to groups, and the data can be read and written through existing APIs. Custom fields cannot be deleted once created and applied.

Description

Custom fields have the following characteristics:

• Their values are expressed in key-value format.
• Key is a string with a length less than 16 bytes. Its name contains only uppercase and lowercase letters, numbers, and underscores (_).
• Value is a buffer customized by the user, which can be binary data. Group-level values have a maximum length of 512 bytes, while member-level values have a maximum length of 64 bytes.
• You can configure the least read permission and the least write permission for each key.

The read and write permissions of a custom field are listed as follows, from high to low:

1. Readable and writable by the app admin.
2. Readable and writable by the group owner.
3. Readable and writable by the group admin.
4. Readable and writable by group members.
5. Readable and writable by anyone, including non-members.

For example, an app needs to extend the GroupLevel field for groups and the value of this field is a number representing the level of a group. If this level information is calculated by the app backend, then the least write permission should be writable by the app admin. If the field is part of the public profile of the group, its least read permission should be readable by anyone, including non-members.

If the value to be stored is a number, we recommend that C and C++ developers store it as a string instead of binary data. For example, when the number to be stored is 1, store it as string 1 instead of binary data 0x01. In the future, IM will offer more operations for custom fields, such as specific mathematical operations on values, which will be performed on the basis of string-type numbers.

Configuration method

Custom fields at these two levels can be configured in the IM console.
To configure member-level custom fields, you need to specify the group type first. Audio-video group and custom group types that are configured based on it do not support custom fields at the group member level, because these types of groups do not store member profiles.
The self read and write permissions indicate whether members can read and write their own member-level custom fields. For example, a member-level customer field named MemberLevel represents the level of a member in a group. Group members can read but not modify their own levels, and therefore their self read and write permissions are set to readable/unwritable for this field.

Custom Callbacks

Third-party callback is an important means to meet the special requirements of apps. It provides users with the capability to customize actions.
IM's group system supports different callbacks. For more information, see Third-Party Callback Overview and Callback Command List.