Channels reference

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
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
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
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
Email	Image	Text	Text	Yes	Yes	Yes	Yes	Text
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)
Twilio (SMS)	Image	Text	No	Text	Text	Text	Text	No
Web Chat	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Yes

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
Direct Line	100	100
Direct Line Speech	100	100
Email	None	None
GroupMe	None	None
LINE	13	99
Microsoft Teams	None	3
Omnichannel
Outlook (preview)
Search (preview)
Twilio (SMS)	None	None
Web Chat	100	100

• For more information about card actions, see Process events within rich cards in the Add media to messages article.
• For more information about suggested actions, see how to Use buttons for input.

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.

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.