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Channel types

Sendbird's SDKs and API provide two basic types of channels. Each type is designed and implemented to support a wide variety of use cases that your business requires. This page presents the differences and characteristics of the two types.


Open channel

An open channel is a public chat that can handle a large number of online users. In open channels, anyone can easily participate without permission. For paid plans, the maximum number of participants supported is 60,000 by default. If you wish to increase the number of participants to greater than 60,000, contact our sales team.

  • Ephemeral: Messages in an ephemeral open channel are not saved in Sendbird's database. This means that old messages pushed out by new ones can't be retrieved as they are one-time data. On the other hand, messages in a persistent open channel are permanently stored in the database, which is the default.

  • Dynamic partitioning: Dynamic partitioning open channels are designed to accommodate an even larger number of users using a set number of subchannels, starting from 2,000 to 60,000 participants. This new system, called dynamic partitioning, enables flexible scaling of open channels by creating or merging subchannels within the open channels and evenly allocating participants among the subchannels while providing a seamless and well-paced chat experience to all users.

  • Classic: A single classic open channel can accommodate up to 1,000 simultaneous users in a Twitch-style public chat.


Group channel

A group channel is a chat that allows close interactions among a limited number of users. In order to join this type of channel, an invitation from a channel member is required by default. Depending on how you implement the joining process in your application, a user who is invited to a group channel can accept or decline the invitation. However, various properties can be leveraged to design different types of group channels that suit your use cases, such as Twitter-style 1-on-1 direct messaging, WhatsApp-style group chat, and more.

  • Public vs. Private: A public group channel can be joined by any user without an invitation. Up to 100 users can join the public group channel. On the other hand, a private group channel only accepts users with invitations by default.

  • Distinct: The distinct option determines whether to resume an old channel or to create an entirely new one when someone attempts to open a new channel with a pre-existing member combination. If there is a group channel with those members, the attempt will re-start the existing channel that has their chat history. This is similar to Twitter-style 1-on-1 direct messaging and more. The default value is false.

  • Supergroup: A Supergroup channel is an expanded version of a group channel, which can accommodate more than 2,000 members in one channel. The super option determines whether a newly created channel will be a Supergroup channel or a group channel. When this option is set to true, the distinct option can't be supported.

  • Ephemeral: Messages in an ephemeral group channel are not saved in Sendbird's database. This means that old messages pushed out by new ones can't be retrieved as they are one-time data. On the other hand, messages in a persistent group channel are permanently stored in the database, which is the default.


Open channel vs. Group channel vs. Supergroup channel

The optimal use cases for each channel type can vary as different channels support different features. The following tables compare open channels, group channels, and Supergroup channels in terms of possible use cases and supported features.

Use cases

Choose which channel type to use based on key factors such as the duration of a chat and the number of users participating in it. The following table lists possible use cases for each channel type.

TypeUsed for

Open channel

- Short-lived live events, such as concerts and streaming.
- News-feed type messaging to massive audience, such as Twitter-style feed.
- Events that don't require a permanent membership.

Group channel

- Private 1-on-1 conversations, such as clinical consultations and Instagram-style Direct Messages.
- Public 1-to-N conversations, such as small group discussions among students.
- Invitation-only chats with a handful group of users.

Supergroup channel

- Ask-me-anything type events with a large number of users.
- Midsize conferences for regular updates, such as company-wide meetings.

Features

The following table compares the difference among three types of channels.

Open channelGroup channelSupergroup channel

Maximum number in a channel

* The maximum number can be adjusted depending on use cases. Contact our sales team.

1,000 participants

100 members

2,000 and more members

* The number varies depending on your Sendbird plan.

Accessible by

Anyone within the application

Invited users only if private or anyone if public

Invited users only if private or anyone if public

Ephemeral messaging

Supported

Supported

Supported

Online presence

Supported

Supported

Supported

Last message

N/A

Supported

Supported

UIKit

Supported

Supported

Supported

Operators

Supported

Supported

Supported

Ban users

Supported

Supported

Supported

Mute users

Supported

Supported

Supported

Freeze channels

Supported

Supported

Supported

Delivery receipts

N/A

Supported

N/A

Read receipts

N/A

Supported

N/A

Unread counts

N/A

Supported

Supported

* Up to 100 unread counts are supported.

Typing indicators

N/A

Supported

Supported

* Up to 3 concurrent indicators are supported.

Mention others in message

Supported

Supported

Supported

Mention counts

N/A

Supported

Supported

Reactions

N/A

Supported

Supported

Spam flood protection

Supported

Supported

Supported

Chatbot interface

Supported

Supported

Supported

Smart throttling

Supported (Default: true)

Supported (Default: false)

Supported (Default: false)

Push notifications

N/A

* Push notifications for announcements only.

Supported

* Push notifications for every message sent.

Supported

* Refer to Limitations.

View a channel with its participant list or member list

N/A

Supported

Supported

* Only ten members are retrieved as a preview.
To get an entire list of members, use the list members API instead.

Pagination for participant list or member list

Supported

Supported

Supported

Order of channel list

- Chronological

- Chronological
- Latest last message
- Channel name
- Metadata value

- Chronological
- Latest last message
- Channel name
- Metadata value