Channel Compatibility

This guide defines the normative capability matrix across nativeMsg-supported channel types, provides channel identifier reference strings, and specifies the rules for designing experiences that degrade gracefully across channels.

Channel Identifier Strings

The following strings are used in the action channel property and the condition channelTypes field.

Identifier	Channel Type	Description
rcs	Rich Communication Services	RCS Business Messaging over the native Android messaging app
dsc	DSC	Direct-to-consumer messaging channel with rich card support
dlc	DLC	10DLC SMS/MMS messaging (limited formatting)

Channel identifier strings are case-sensitive. "RCS" and "rcs" are not equivalent in condition or action channel fields.

Feature × Channel Capability Matrix

The table below lists every schema feature and its support status per channel. Where a feature is supported, the exact maximum or constraint is stated. Where a feature is unsupported, the degradation behavior is noted.

Feature	RCS	DSC	DLC
Text message	✓ Max 3072 chars	✓ Max 3072 chars	✓ Max 160 chars per SMS segment; longer messages split into multiple segments
Message title	✓ Max 200 chars	✓ Max 200 chars	✗ Ignored
Media — image	✓ JPEG, PNG, GIF, WebP	✓ JPEG, PNG, GIF	✓ MMS only; file size limits apply per carrier
Media — video	✓ MP4, WebM	✓ MP4	✗ Not supported
Media — audio	✓ MP3, OGG, WAV	✗ Not supported	✗ Not supported
Media — file	✓ PDF and common document types	✓ PDF	✗ Not supported
Buttons — total per message	Max 4	Max 4	✗ Not supported
Button type: weburl	✓	✓	✗
Button type: postback	✓	✓	✗
Button type: call	✓	✓	✗
Button type: text	✓	✓	✗
Button type: location	✓	✗	✗
Button type: viewLocation	✓	✗	✗
Button type: calendar	✓	✗	✗
Button type: datetime	✓	✗	✗
Button title max	25 chars	25 chars	N/A
Button payload max	1000 chars	1000 chars	N/A
Quick replies	✓ Max 13	✓ Max 13	✗ Not supported
Quick reply title max	25 chars	25 chars	N/A
Quick reply — image	✓ (imageUrl)	✓ (imageUrl)	✗
Quick reply type: location	✓	✗	✗
Quick reply type: datetime	✓	✗	✗
Quick reply type: calendar	✓	✗	✗
Carousel	✓ Min 2, Max 10 cards	✓ Min 2, Max 10 cards	✗ Not supported
List	✓ Min 2, Max 4 items	✓ Min 2, Max 4 items	✗ Not supported
Rich card (standalone)	✓	✓	✗ Not supported
Rich card — VERTICAL orientation	✓	✓	✗
Rich card — HORIZONTAL orientation	✓	✓	✗
Rich card title max	200 chars	200 chars	N/A
Rich card description max	2000 chars	2000 chars	N/A
Rich card buttons max	4	4	N/A
mediaHeight: SHORT	✓	✓	✗
mediaHeight: MEDIUM	✓	✓	✗
mediaHeight: TALL	✓	✓	✗
imageAlignment: LEFT / RIGHT	✓ (HORIZONTAL only)	✓ (HORIZONTAL only)	✗
waitFor: text	✓	✓	✓
waitFor: number	✓	✓	✓
waitFor: datetime	✓	✓	✓ (typed by user)
waitFor: coordinates	✓	✓	✗
waitFor: file	✓	✓	✗
waitFor: quick reply	✓	✓	✗
waitFor: multi select	✓	✓	✗
send.email	✓	✓	✓
send.request	✓	✓	✓
send.note	✓	✓	✓
send.rss	✓	✓	✗
assignTags	✓	✓	✓
assignAttributes	✓	✓	✓
updateSettings.conversation.priority	✓	✓	✓
updateSettings.rcsExperience.enabled	✓	✗	✗
subscribe	✓	✓	✓
Webview (webviewViewMode)	✓ full, half, tall	✓ full, half, tall	✗

Features listed as ✗ for a channel are silently ignored or cause a degraded experience — they do not produce a runtime error. Always test your experience on each target channel before deploying.

Designing for Cross-Channel Compatibility

Normative Rules

1. Channel-restrict rich actions. Any action that uses a feature not supported on all target channels MUST include either a channel property (restricting execution to the capable channel) or a conditions array with a channelTypes filter.

2. Always provide a text fallback. For every rich-content action (carousel, list, richCard, buttons), a parallel action restricted to non-rich channels MUST be defined, sending equivalent information as plain text.

3. Do not rely on button-triggered execute on DLC. On DLC channels, buttons are not rendered and their execute callbacks never fire. All workflow branching on DLC MUST be driven by user-typed text or keyword matching.

4. Quick replies MUST NOT be the only navigation mechanism. Any workflow that relies on quick reply selection for progression MUST include a waitFor step accepting "text" in addition to "quick reply", so text-only channel users can respond.

5. Test DLC text length. Messages intended for DLC MUST be designed to fit within 160 characters where possible, or explicitly planned for multi-segment delivery. Attribute placeholder substitution happens before length evaluation; account for the expanded text length.

Channel-Restriction Pattern

Use the channel property on actions to serve channel-appropriate content from a single workflow:

{
  "name": "Cross-Channel Announcement",
  "workflows": [
    {
      "name": "send-announcement",
      "intents": ["announcement"],
      "actions": [
        {
          "name": "rich-announcement-rcs",
          "channel": "rcs",
          "send": {
            "message": {
              "title": "New Feature: Live Order Tracking",
              "text": "Track your order in real time with our new interactive map.",
              "mediaType": "image",
              "media": "https://cdn.acme.com/features/live-tracking-preview.jpg",
              "richCard": {
                "cardOrientation": "VERTICAL",
                "mediaHeight": "MEDIUM"
              },
              "buttons": [
                {
                  "type": "weburl",
                  "title": "Try it now",
                  "payload": "https://shop.acme.com/track"
                }
              ]
            }
          }
        },
        {
          "name": "rich-announcement-dsc",
          "channel": "dsc",
          "send": {
            "message": {
              "title": "New Feature: Live Order Tracking",
              "text": "Track your order in real time with our new interactive map.",
              "buttons": [
                {
                  "type": "weburl",
                  "title": "Try it now",
                  "payload": "https://shop.acme.com/track"
                }
              ]
            }
          }
        },
        {
          "name": "text-announcement-dlc",
          "channel": "dlc",
          "send": {
            "message": {
              "text": "New: Live order tracking is here! Visit acme.com/track to try it. Reply STOP to opt out."
            }
          }
        }
      ]
    }
  ]
}

Condition-Based Channel Routing

Use conditions with channelTypes when you need to branch execution logic (not just content) by channel:

{
  "name": "check-rcs-capable",
  "conditions": [
    {
      "channelTypes": ["rcs", "dsc"]
    }
  ],
  "send": {
    "message": {
      "text": "Choose an option below:",
      "quickReplies": [
        { "type": "text", "title": "Option A", "payload": "opt_a" },
        { "type": "text", "title": "Option B", "payload": "opt_b" }
      ]
    }
  }
}

{
  "name": "dlc-text-prompt",
  "conditions": [
    {
      "channelTypes": "dlc"
    }
  ],
  "send": {
    "message": {
      "text": "Reply A for Option A or B for Option B."
    }
  }
}

RSS Feed Channel Restriction

RSS feed rendering (send.rss) is only supported on RCS and DSC. Always restrict this action and provide a fallback:

{
  "name": "send-news-rcs",
  "channel": "rcs",
  "send": {
    "rss": {
      "url": "https://blog.acme.com/feed.xml",
      "preferedLayout": "carousel"
    }
  }
}

{
  "name": "send-news-dlc",
  "channel": "dlc",
  "send": {
    "message": {
      "text": "Read our latest articles at blog.acme.com"
    }
  }
}