Channels reference

  • Article

APPLIES TO: SDK v4

This article outlines channel support for various Bot Framework features:

  • The activity types each channel can send or receive.
  • The card types each channel can display, including Adaptive Cards.
  • Card action and suggested action support on each channel.
  • A general classification of the different activity types.

For detailed information about the structure of activities and cards at the protocol level, see the Bot Framework activity and card schemas.

Adaptive Cards is a separate technology. For more information, see adaptivecards.io.

Activity support by channel

The following table indicates whether a given channel can send a given activity type to your bot. Within the table, the following terms have the following meanings.

Term Meaning
Yes The bot can receive this activity from the channel.
No The bot can't receive this activity from the channel.
Undetermined Currently undetermined.
Channel Contact relation update Conversation update End of conversation Event Installation update Invoke Message Message reaction Message update Message delete Typing
Alexa No No Yes Yes No No Yes No No No No
Azure Communication Services Chat No Yes No Yes No No Yes No Yes Yes Yes
Direct Line No Yes Yes Yes Yes No Yes No No No Yes
Direct Line Speech Yes
Email No No No Undetermined No No Yes No No No No
Facebook No Yes No Yes No No Yes Yes No No No
GroupMe No Yes No Undetermined No No Yes No No No No
LINE No Yes No Yes No No Yes No No No No
Microsoft Teams No Yes No Undetermined No Yes Yes Yes Yes Yes No
Omnichannel Yes
Outlook (preview) Yes
Search (preview) Yes
Slack No Yes No Undetermined No No Yes No Yes Yes No
Telegram No Yes No Undetermined No No Yes No Yes Undetermined No
Twilio (SMS) No No No Undetermined No No Yes No No No No
Web Chat No Yes Yes Yes Yes No Yes No No No Yes

Support for event and invoke activities varies by the activity's name and varies by channel.

Card support by channel

The following table indicates whether a given channel can render a given card type. Even if a channel can render a card type, the channel may not support all features on the card. Before releasing your bot, test the behavior of each card your bot can send.

Within the table, the following terms have the following meanings.

Term Meaning
Yes The card is supported on this channel; however, any given channel may only support a subset of card actions or may limit the number of actions allowed on each card.
No The card isn't supported on this channel.
Partial Partial support. This channel might not display the card if the card contains inputs or buttons. Level of support varies by channel.
Image Card is converted to image.
Text Card is converted to unformatted text. Links may not be clickable, images may not display, and media may not be playable. Level of support varies by channel.
Channel Adaptive Card Animation card Audio card Hero card Receipt card Sign-in card Thumbnail card Video card
Alexa No No No Yes No Yes No No
Azure Communication Services Chat Yes* Yes Yes Yes Yes Yes Yes Yes
Email Image Text Text Yes Yes Yes Yes Text
Facebook Image, partial Yes Yes Yes Yes Yes Yes Yes
GroupMe Image Text Text Text Text Text Text Text
LINE Image, partial Yes Text Yes Yes Yes Yes Text
Microsoft Teams Yes No No Yes Yes Yes Yes No
Omnichannel
Outlook (preview)
Search (preview)
Slack Image Yes Text Text Yes Yes Text Text
Telegram Image, partial Yes Text Yes Yes Yes Yes Yes
Twilio (SMS) Image Text No Text Text Text Text No
Web Chat Yes Yes Yes Yes Yes Yes Yes Yes

Note

  • The Direct Line channel technically supports all cards, but it's up to the client to implement them.
  • *For Azure Communication Services Chat, Adaptive cards are only supported within Azure Communication Services use cases, and not for Azure Communication Services to Teams use cases.

Card action support by channel

The following table shows the maximum number of suggested actions and card actions that a given channel supports. A value of "None" indicates that the action type isn't supported in the channel.

Channel Suggested actions Card actions
Alexa None None
Azure Communication Services Chat
Direct Line 100 100
Direct Line Speech 100 100
Email None None
Facebook 11 3
GroupMe None None
LINE 13 99
Microsoft Teams None 3
Omnichannel
Outlook (preview)
Search (preview)
Slack None 100
Telegram 100 100
Twilio (SMS) None None
Web Chat 100 100

Activity categories

Activities can be split into separate categories. For a detailed description of each type of activity, and the information that each type of activity contains, see the Bot Framework activity schema.

Welcome

This category includes the conversationUpdate and contactRelationUpdate activities.

  • Many channels send conversation update activities.
    • Often, bot welcome behavior is triggered by the conversation update activity. However, producing reliable welcome behavior might require the use of conversation or user state.
  • Some channels send contact relation update activities.
    • If your bot uses these channels, you may need to include logic for this activity in your bot's welcome behavior.

Conversational

This category includes the message, messageReaction, and endOfConversation activities.

  • All channels can send and receive message activities.
    • For bots that use dialogs, message activities should generally be passed into the dialog.
  • Some channels can send and receive message reaction activities.
    • Depending on the design of your bot, you might pass message reaction activities into a dialog.
    • Message reaction activities reference previous messages by ID.
  • End of conversation activities signal the end of a conversation from the sender's perspective.
    • End of conversation activities are used in bot-to-bot communication for skills.

Tip

A message reaction includes things like a thumbs up on a previous comment. They can happen out of order, so they can be thought of as similar to buttons. This activity type can be sent by the Teams channel.

Message update and delete

This category includes the messageUpdate and messageDelete activities.

  • Teams supports the message update and delete activities.

Application extensibility

This category includes the event and invoke activities. The meaning of the activity is defined by its name field, which is meaningful within the scope of a channel.

  • An application that owns both the client and server can use event activities to communicate programmatic information between the client and server.
    • Event activities, like most activity types, are asynchronous.
    • Direct Line and Web Chat use event activities as an extensibility mechanism.
  • Invoke activities are specific to an application and not something a client would define.
    • Invoke activities, unlike other activity types, are synchronous. (Invoke is currently the only activity type that triggers a request-reply behavior on the bot.)
    • Microsoft Teams uses invoke activities and defines a few Teams-specific invoke activities.

Authentication

For the OAuth prompt to work with dialogs, the TeamsVerification invoke activity must be forwarded to the dialog.

Uncategorized

The installationUpdate, typing, and handoff activities don't meaningfully fit into the other categories.

  • Installation update activities represent an installation or uninstallation of a bot within an organizational unit of a channel.
  • Typing activities represent ongoing input from a user or a bot.
  • Handoff activities request or signal a change in focus between elements inside a bot. The handoff activity is different from an event activity that has the name "handoff".

Out of use (includes payment specific invoke)

These activity types are no longer in use:

  • deleteUserData
  • handoff
  • ping
  • Address invoke
  • PaymentRequest invoke

Additional information

All channels can send and receive message activities.

Tip

When adding support for a channel to your bot, familiarize yourself with the channel's developer docs. Each channel has different limitations on various aspects of a conversation. Some of the differences include:

  • How much time the bot has to handle each HTTP request.
  • Whether a bot can send an activity that's not in response to a specific user activity.
  • How many messages the bot can send within a given time frame.
  • How a card renders and which cards are supported.