iOS
Channel Type

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 by nature that can handle a large number of online users. A single open channel can accommodate up to 1,000 simultaneous users in a Twitch-style public chat, and anyone can easily participate without permission. This maximum number of participants can increase per request.

  • 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.

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.

  • 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.

  • Public: A public group channel can be joined by any user without an invitation. Users can freely join the channel if they want to. On the other hand, a private group channel only accepts invited users by default.

  • 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

Open channelGroup channel

Open and visible to

Anyone within the application

Invited users if private and anyone if public

Number of people

Up to 1,000 participants

Up to 100 members (can be increased per request)

How to create

Dashboard / Platform API / Client SDK

Platform API / Client SDK

Ephemeral messaging

Supported

Supported

Add users 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 others in message

Supported

Supported

Chatbot interface

N/A

Supported

Spam flood protection

Supported

Supported

Smart throttling

Supported

N/A