Google Chat Messages

Send messages to Google Chat spaces via incoming webhooks. Produces text messages, rich cards (cardsV2), and threaded replies.

What You Produce

• Text messages with Google Chat formatting
• Rich card messages (cardsV2) with headers, sections, widgets
• Threaded conversations
• Reusable webhook sender utility

Workflow

Step 1: Get Webhook URL

In Google Chat:

1. Open a Space > click space name > Manage webhooks
2. Create webhook (name it, optionally add avatar URL)
3. Copy the webhook URL

Store the URL as an environment variable or in your secrets manager — never hardcode.

Step 2: Choose Message Type

Need	Type	Complexity
Simple notification	Text message	Low
Structured info (status, digest)	Card message (cardsV2)	Medium
Ongoing updates	Threaded replies	Medium
Action buttons (open URL)	Card with buttonList	Medium

Step 3: Send the Message

Use assets/webhook-sender.ts for the sender utility. Use assets/card-builder.ts for structured card construction.

Text Formatting

Google Chat does NOT use standard Markdown.

Format	Syntax	Example
Bold	*text*	*important*
Italic	_text_	_emphasis_
Strikethrough	~text~	~removed~
Monospace	`text`	`code`
Code block	```text```	Multi-line code
Link	<url|text>	<https://example.com|Click here>
Mention user	<users/USER_ID>	<users/123456>
Mention all	<users/all>	<users/all>

Not supported: **double asterisks**, headings (###), blockquotes, tables, images inline.

Text Message Example

await sendText(webhookUrl, '*Build Complete*\n\nBranch: `main`\nStatus: Passed\n<https://ci.example.com/123|View Build>');

cardsV2 Structure

Cards use the cardsV2 format (recommended over legacy cards).

const message = {
  cardsV2: [{
    cardId: 'unique-id',
    card: {
      header: {
        title: 'Card Title',
        subtitle: 'Optional subtitle',
        imageUrl: 'https://example.com/icon.png',
        imageType: 'CIRCLE'  // or 'SQUARE'
      },
      sections: [{
        header: 'Section Title',  // optional
        widgets: [
          // widgets go here
        ]
      }]
    }
  }]
};

Widget Reference

All widget types available in cardsV2 sections.

textParagraph

Formatted text block. Supports Google Chat formatting (*bold*, _italic_, <url|text>).

{
  textParagraph: {
    text: '*Status*: All systems operational\n_Last checked_: 5 minutes ago'
  }
}

decoratedText

Labelled value with optional icons. Most versatile widget for key-value data.

Basic:

{
  decoratedText: {
    topLabel: 'Environment',
    text: 'Production',
    bottomLabel: 'Last deployed 2h ago'
  }
}

With start icon:

{
  decoratedText: {
    topLabel: 'Status',
    text: 'Healthy',
    startIcon: { knownIcon: 'STAR' }
  }
}

With custom icon URL:

{
  decoratedText: {
    topLabel: 'GitHub',
    text: 'PR #142 merged',
    startIcon: {
      iconUrl: 'https://github.githubassets.com/favicons/favicon.svg',
      altText: 'GitHub'
    }
  }
}

With button:

{
  decoratedText: {
    topLabel: 'Alert',
    text: 'CPU at 95%',
    button: {
      text: 'View',
      onClick: { openLink: { url: 'https://monitoring.example.com' } }
    }
  }
}

Clickable (whole widget):

{
  decoratedText: {
    text: 'View full report',
    wrapText: true,
    onClick: { openLink: { url: 'https://reports.example.com' } }
  }
}

With wrap text:

{
  decoratedText: {
    topLabel: 'Description',
    text: 'This is a longer description that should wrap to multiple lines instead of being truncated',
    wrapText: true
  }
}

buttonList

One or more action buttons. Buttons open URLs or trigger actions.

Single button:

{
  buttonList: {
    buttons: [{
      text: 'Open Dashboard',
      onClick: { openLink: { url: 'https://dashboard.example.com' } }
    }]
  }
}

Multiple buttons:

{
  buttonList: {
    buttons: [
      {
        text: 'Approve',
        onClick: { openLink: { url: 'https://app.example.com/approve/123' } },
        color: { red: 0, green: 0.5, blue: 0, alpha: 1 }
      },
      {
        text: 'Reject',
        onClick: { openLink: { url: 'https://app.example.com/reject/123' } }
      }
    ]
  }
}

Button with icon:

{
  buttonList: {
    buttons: [{
      text: 'View on GitHub',
      icon: { knownIcon: 'BOOKMARK' },
      onClick: { openLink: { url: 'https://github.com/org/repo/pull/42' } }
    }]
  }
}

image

Standalone image widget.

{
  image: {
    imageUrl: 'https://example.com/chart.png',
    altText: 'Monthly usage chart'
  }
}

divider

Horizontal line separator between widgets.

{ divider: {} }

Collapsible Sections

Sections can be collapsed with only the first N widgets visible:

{
  header: 'Details',
  collapsible: true,
  uncollapsibleWidgetsCount: 2,  // Show first 2, collapse rest
  widgets: [
    { decoratedText: { topLabel: 'Status', text: 'Active' } },
    { decoratedText: { topLabel: 'Region', text: 'AU' } },
    // These start collapsed
    { decoratedText: { topLabel: 'Instance', text: 'prod-01' } },
    { decoratedText: { topLabel: 'Memory', text: '2.1 GB' } },
    { decoratedText: { topLabel: 'CPU', text: '45%' } }
  ]
}

Known Icons

Icons available via knownIcon in decoratedText and button widgets.

{ startIcon: { knownIcon: 'STAR' } }
// or
{ icon: { knownIcon: 'EMAIL' } }

Icon Name	Use For
AIRPLANE	Travel, flights
BOOKMARK	Save, reference, links
BUS	Transport, transit
CAR	Driving, transport
CLOCK	Time, duration, schedule
CONFIRMATION_NUMBER_ICON	Tickets, bookings
DESCRIPTION	Documents, files
DOLLAR	Money, pricing, cost
EMAIL	Email, messages
INVITE	Invitations
MAP_PIN	Location, address
MEMBERSHIP	Members, users
MULTIPLE_PEOPLE	Teams, groups
OFFER	Deals, promotions
PERSON	Individual user
PHONE	Phone number, calls
SHOPPING_CART	Commerce, purchases
STAR	Rating, favourite, important
STORE	Shop, retail
TICKET	Tickets, events
VIDEO_CAMERA	Video, meetings

For icons not in the list, use iconUrl with any publicly accessible image (square, ideally 24x24 or 48x48 pixels).

Threading

Thread messages together using threadKey:

// First message — creates thread
const response = await sendCard(webhookUrl, card, {
  threadKey: 'deploy-2026-02-16'
});

// Reply to thread — append &messageReplyOption=REPLY_MESSAGE_FALLBACK_TO_NEW_THREAD
const threadUrl = `${webhookUrl}&messageReplyOption=REPLY_MESSAGE_FALLBACK_TO_NEW_THREAD`;
await sendCard(threadUrl, replyCard, {
  threadKey: 'deploy-2026-02-16'
});

The threadKey is a client-assigned string. Use consistent keys for related messages (e.g., deploy-{date}, alert-{id}).

Common Patterns

Notification Card

import { buildCard, sendCard } from './assets/card-builder';
import { sendWebhook } from './assets/webhook-sender';

const card = buildCard({
  cardId: 'deploy-notification',
  title: 'Deployment Complete',
  subtitle: 'production - v2.1.0',
  imageUrl: 'https://example.com/your-icon.png',
  sections: [{
    widgets: [
      { decoratedText: { topLabel: 'Environment', text: 'Production' } },
      { decoratedText: { topLabel: 'Version', text: 'v2.1.0' } },
      { decoratedText: { topLabel: 'Status', text: '*Healthy*', startIcon: { knownIcon: 'STAR' } } },
      { buttonList: { buttons: [{ text: 'View Deployment', onClick: { openLink: { url: 'https://dash.example.com' } } }] } }
    ]
  }]
});

Digest Card (Weekly Summary)

const digest = buildCard({
  cardId: 'weekly-digest',
  title: 'Weekly Summary',
  subtitle: `${count} updates this week`,
  sections: [
    {
      header: 'Highlights',
      widgets: items.map(item => ({
        decoratedText: { text: item.title, bottomLabel: item.date }
      }))
    },
    {
      widgets: [{
        buttonList: {
          buttons: [{ text: 'View All', onClick: { openLink: { url: dashboardUrl } } }]
        }
      }]
    }
  ]
});

Error Prevention

Mistake	Fix
**bold** in text	Use *bold* (single asterisks)
[text](url) links	Use <url|text> format
Missing cardsV2 wrapper	Wrap card in { cardsV2: [{ cardId, card }] }
Thread replies not threading	Append &messageReplyOption=REPLY_MESSAGE_FALLBACK_TO_NEW_THREAD to webhook URL
Webhook returns 400	Check JSON structure — common issue is missing text or cardsV2 at top level
Card not showing	Ensure sections has at least one widget

Asset Files

File	Purpose
assets/types.ts	TypeScript type definitions for cardsV2
assets/card-builder.ts	Utility to build card messages
assets/webhook-sender.ts	POST to webhook with error handling