Channel Types

We recommend that you understand the following terms before proceeding with the rest of this guide.


Open Channel

Open Channel is a public chat by nature and it can handle a large number of participation online. In this channel type, anyone can enter and participate in the chat without permission. A single channel can handle up to 1000, simultaneous users like Twitch-style public chat. This default number of participants can increase per request.

  • Ephemeral : In an Ephemeral open channel, its messages are not saved in the database of SendBird infrastructure. So the old messages lifted up by new ones can't be retrieved because they are one-time data. On the other hand, in a Persistent open channel (by default), its messages are stored permanently in the database.

Group Channel

A Group Channel is a chat that provides close interactions among limited number of people. By default, a user can join the chat as a new member through an invitation by another user who is already a member of the chat room. But by using various properties for its functionalities, you can design and make various types of group channels which are fit to your use cases, such as Twitter-style 1-on-1 direct messaging, WhatsApp-sytle closed group chat, and so on.

  • Distinct : A Distinct group channel is always reused for the same members. If a new member is invited, or if a member leaves the channel, then the Distinct property is disabled automatically. With the Distinct property, you can reuse the group channel for the same members like Twitter Direct Messages-style 1-on-1 chatting.

  • Public : A Public group channel can take any users with no invitation. Users can freely join the channel if they want to. On the other hand, a Private group channel (default setting) accepts the invited users only.

  • Ephemeral : In an Ephemeral group channel, its messages are not saved in the database of SendBird infrastructure. As such, the old messages that scroll up beyond the user's display due to new messages cannot be retrieved. On the other hand, in a Persistent group channel (default setting), its messages are stored permanently in the database.


Open Channel vs. Group Channel

Open Channel Group Channel
Open and visible to Anyone within the application Who is invited if private (Anyone if public)
Number of people Up to 1,000 participants Up to 100 members
How to create Dashboard / Platform API / Client SDK Platform API / Client SDK
Ephemeral messaging Supported Supported
Add users of an application as friends Supported Supported
Operators Supported Supported
Ban user Supported Supported
Mute user Supported Supported
Freeze channel Supported Supported
Push notifications N/A Supported
Unread counts N/A Supported
Read receipts N/A Supported
Typing indicators N/A Supported
Mention members in messages N/A Supported
Chatbot interface N/A Supported
Spam flood protection Supported Supported
Smart throttling Supported N/A