Messaging Extensions Overview

Introduction

Greentic supports multiple messaging platforms through messaging extension packs. Each extension is a WASM pack that handles:

Ingress - Receiving messages from the platform
Egress - Sending messages to the platform
Operations - Platform-specific features such as buttons, cards, threads, file handling, and webhook setup

The current catalog includes Slack, Microsoft Teams, Telegram, WhatsApp, WebChat, WebChat GUI, Webex, SMTP Email, Microsoft Graph Email, HTTP, and WebSocket messaging packs.

Available Providers

Slack Connect to Slack workspaces with full app support

Microsoft Teams Integrate with Microsoft Teams channels and chats

Telegram Build Telegram bots with buttons and inline keyboards

WhatsApp Connect to WhatsApp Business Platform Cloud API

WebChat Embed chat widget in your website

Webex Integrate with Webex messaging

Email Send SMTP email and use Microsoft Graph mail

HTTP Map inbound HTTP requests and build outbound HTTP calls

WebSocket Map inbound WebSocket frames and build outbound frames

Architecture

External Platform (Slack/Teams/Telegram)
    │
    ▼ Webhook
┌─────────────────────────────────────────┐
│           Ingress Component             │
│   (Parse platform-specific format)      │
└─────────────────────────────────────────┘
    │
    ▼ Normalized Message
┌─────────────────────────────────────────┐
│           Runtime Router                │
│  greentic.messaging.ingress.{tenant}... │
└─────────────────────────────────────────┘
    │
    ▼
┌─────────────────────────────────────────┐
│           Flow Executor                  │
│      (Process with your flows)          │
└─────────────────────────────────────────┘
    │
    ▼
┌─────────────────────────────────────────┐
│           Runtime Router                │
│  greentic.messaging.egress.{tenant}...  │
└─────────────────────────────────────────┘
    │
    ▼ Platform-specific format
┌─────────────────────────────────────────┐
│           Egress Component              │
│     (Format for platform API)           │
└─────────────────────────────────────────┘
    │
    ▼ API Call
External Platform

Message Normalization

All providers normalize messages to a common format:

pub struct NormalizedMessage {
    pub id: String,
    pub channel_id: String,
    pub sender_id: String,
    pub sender_name: Option<String>,
    pub content: String,
    pub timestamp: u64,
    pub reply_to: Option<String>,
    pub attachments: Vec<Attachment>,
    pub metadata: Option<Value>,
}

This allows your flows to work across any messaging platform without modification.

Extension Configuration

Messaging extensions are normally selected with gtc wizard, which writes the bundle metadata and pack references for you. The built-in catalog uses OCI references such as:

oci://ghcr.io/greenticai/packs/messaging/messaging-slack:latest
oci://ghcr.io/greenticai/packs/messaging/messaging-teams:latest
oci://ghcr.io/greenticai/packs/messaging/messaging-telegram:latest
oci://ghcr.io/greenticai/packs/messaging/messaging-whatsapp:latest
oci://ghcr.io/greenticai/packs/messaging/messaging-webchat:latest
oci://ghcr.io/greenticai/packs/messaging/messaging-webchat-gui:latest
oci://ghcr.io/greenticai/packs/messaging/messaging-webex:latest
oci://ghcr.io/greenticai/packs/messaging/messaging-email:latest
oci://ghcr.io/greenticai/packs/messaging/messaging-microsoft-email:latest
oci://ghcr.io/greenticai/packs/messaging/messaging-http:latest
oci://ghcr.io/greenticai/packs/messaging/messaging-websocket:latest

Setup Answers

Run gtc setup ./my-bundle interactively, or provide an answers file generated with gtc setup --dry-run --emit-answers answers.json ./my-bundle.

{
  "greentic_setup_version": "1.0.0",
  "tenant": "demo",
  "team": null,
  "env": "dev",
  "platform_setup": {
    "static_routes": {
      "public_web_enabled": true,
      "public_base_url": "https://example.trycloudflare.com",
      "public_surface_policy": "enabled",
      "default_route_prefix_policy": "pack_declared",
      "tenant_path_policy": "pack_declared"
    },
    "deployment_targets": [],
    "tunnel": {
      "mode": "cloudflared"
    }
  },
  "setup_answers": {
    "messaging-telegram": {
      "public_base_url": "https://example.trycloudflare.com",
      "api_base_url": "https://api.telegram.org",
      "telegram_bot_token": "123456789:ABCdefGHI..."
    },
    "messaging-slack": {
      "slack_configuration_access_token": "xoxe.xoxp-...",
      "slack_configuration_refresh_token": "xoxe-1-..."
    },
    "messaging-webex": {
      "webex_bot_token": "your-webex-bot-access-token"
    }
  }
}

Provider setup is pack-owned. Hosts should use the installed pack’s setup schema and metadata instead of inferring provider-specific fields. New answers files keep provider fields under setup_answers; the top-level platform_setup block carries static routes, deployment targets, and tunnel preferences. Several providers generate internal secrets during setup, including the Webex webhook secret and WebChat GUI JWT signing key.

Setup Actions And Add To X Links

Provider setup has two separate action types:

Provider-specific setup actions run during setup. For example, Slack’s setup action is Setup Slack App because it creates or updates the Slack app configuration.
Generic post-setup actions are declared by the pack with greentic.setup.actions.v1. Setup hosts can render these after provider setup completes, without hard-coding Slack, Teams, Telegram, or Webex behavior.

The current messaging packs expose these generic actions:

Provider	Label	URL source
Slack	Add to Slack	`slack_add_url` returned by Slack setup
Microsoft Teams	Add to Teams	`add_to_teams_url` returned by Teams setup
Telegram	Add to Telegram	`https://t.me/{bot_username}`
Webex	Add to WebEx	`https://web.webex.com/teams/messages/new?email={bot_email}`

Each action can be displayed as a button, copied as a URL, or rendered as an HTML snippet by setup tools. If a bundle includes more than one provider with setup actions, the final setup screen should show all available actions.

Current Setup Model

Provider	Setup model
Slack	App registration and OAuth install flow. The setup step is labeled Setup Slack App. Setup stores `slack_app_id` plus Slack configuration access/refresh tokens for manifest updates, then exposes a generic Add to Slack post-setup action.
Microsoft Teams	`messaging-teams` uses a provider-owned setup wizard and backend contract. It guides Microsoft device-code sign-in, creates or reuses the Bot Framework app identity, registers the active Greentic endpoint, publishes the Teams app, installs it for the setup user, and exposes Add to Teams. `messaging-teams-graph` remains available for Graph channel sends/subscriptions.
Telegram	Bot token, Telegram API base URL, optional default chat ID, and public webhook URL.
WhatsApp	Meta Cloud API phone number, business account, Graph API base URL/version, access token, verify token, and public webhook URL.
WebChat GUI	Hosted browser UI. Defaults to `websocket`; setup generates the JWT signing key and supports optional OAuth/branding fields.
WebChat	Direct Line-compatible provider. Requires public base URL, mode, and JWT signing key when used without the GUI pack.
Webex	Bot access token only. Setup generates the webhook secret and reconciles direct-message, mention, and card-action webhooks.
Email	`messaging-email` is SMTP. `messaging-microsoft-email` is Microsoft Graph mail with delegated OAuth credentials.
HTTP	Answer-owned provider generated from `build-answer.json`. It maps inbound HTTP requests into normalized messages and builds outbound HTTP request payloads.
WebSocket	Answer-owned provider generated from `build-answer.json`. It maps inbound WebSocket frames into normalized events and builds outbound WebSocket frames.

Network Access

Messaging packs do not require provider-specific local listening ports. They use the Greentic runtime’s public HTTP(S) listener for browser traffic and platform webhooks. In production, expose that listener through HTTPS on port 443; in local development, gtc setup can use a tunnel such as Cloudflare Tunnel to forward a public HTTPS URL to the local runtime port.

Provider	Incoming to Greentic	Outgoing from Greentic
Slack	HTTPS `443` from Slack Events API, interactive components, slash commands, and OAuth redirects to the public ingress URL	HTTPS `443` to `slack.com` and `api.slack.com` for OAuth, Web API calls, app registration, and manifest updates
Microsoft Teams	HTTPS `443` from Microsoft Bot Framework to the runtime ingress endpoint. Graph mode also uses HTTPS `443` Graph change and lifecycle notifications	HTTPS `443` to `login.microsoftonline.com`, `graph.microsoft.com`, Azure management endpoints used by setup, and Bot Framework service URLs
Telegram	HTTPS `443` from Telegram webhook delivery to the public ingress URL	HTTPS `443` to `api.telegram.org` or the configured Telegram API base URL
WhatsApp	HTTPS `443` from Meta webhook verification and message callbacks	HTTPS `443` to `graph.facebook.com` or the configured Meta Graph API base URL
Webex	HTTPS `443` from Webex `messages.created` and `attachmentActions.created` webhooks	HTTPS `443` to `webexapis.com`
WebChat / WebChat GUI	Browser HTTPS `443` and WSS `443` to the public WebChat route. Local development may use an unencrypted localhost port behind a tunnel	Usually no third-party messaging egress. OAuth/OIDC login uses HTTPS `443` to the configured identity provider
Email	SMTP has no Greentic inbound port. Microsoft Graph mail subscriptions, when enabled by the installed pack, use HTTPS `443` callbacks	SMTP over TCP `587` with STARTTLS or TCP `465` with implicit TLS. Microsoft Graph mail uses HTTPS `443` to Microsoft identity and Graph endpoints
HTTP	HTTPS `443` to the public runtime route when external systems call Greentic; local test harnesses can use the local runtime port	Configured outbound HTTP or HTTPS endpoints
WebSocket	WSS `443` to the public runtime route when clients connect through TLS; local test harnesses can use WS on the local runtime port	Configured outbound WS or WSS endpoints

Common Features

Text Messages

All providers support basic text messages:

- id: reply
  type: reply
  config:
    message: "Hello! How can I help?"

Rich Content

Most providers support rich content:

- id: send_card
  type: adaptive-card
  config:
    card: "cards/welcome.json"

Buttons/Actions

Interactive elements (provider-dependent):

- id: ask_choice
  type: reply
  config:
    message: "What would you like to do?"
    buttons:
      - label: "Get Help"
        action: "help"
      - label: "Contact Support"
        action: "support"

Attachments

File and media support:

- id: send_file
  type: reply
  config:
    message: "Here's your report"
    attachments:
      - type: file
        url: "https://example.com/report.pdf"
        name: "report.pdf"

Multi-Channel Flows

Write flows that work across channels:

name: universal_handler
version: "1.0"

nodes:
  - id: greet
    type: reply
    config:
      # Works on any platform
      message: "Hello! I'm your assistant."
    to: ask_intent

  - id: ask_intent
    type: reply
    config:
      message: "How can I help you today?"
      # Buttons render differently per platform
      buttons:
        - label: "Get Started"
          action: "start"
        - label: "Help"
          action: "help"

triggers:
  - type: message
    pattern: "hello|hi"
    target: greet

Provider Comparison

Feature	Slack	Teams	Telegram	WhatsApp	WebChat	Webex	Email	HTTP	WebSocket
Text	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Payload mapped to text	Frame mapped to text
Native rich layout	Block Kit	Adaptive Cards	Inline/reply keyboards	Interactive messages/templates	Adaptive Cards	Adaptive Cards	HTML	JSON payloads	JSON frames
Adaptive Card handling	Transformed	Native	Transformed	Transformed	Native	Native subset	Transformed to HTML	Caller-defined	Caller-defined
Buttons	Yes	Yes	Yes	Yes	Yes	Yes	Links/forms	Caller-defined	Caller-defined
Files	Yes	Yes	Yes	Yes	Yes	Yes	Attachments	URLs or payload metadata	URLs or frame metadata
Threads/replies	Threads	Conversations/replies	Reply-to/topics only	No	Conversation history	Threads/spaces	Email headers	Request correlation	Connection/session correlation
Reactions	Platform-dependent	Platform-dependent	No	No	No	No	No	No	No

Next Steps

Choose a provider to get started:

Telegram - Easiest setup, great for testing
Slack - Full-featured workspace integration
WebChat - Embed in your website