Group vs DM Handling

When building automation, you often need different behavior for group messages versus direct messages. This guide covers detection, filtering, and admin exemptions.

Detecting Group Messages

By Chat ID Suffix

Group chat IDs end with @g.us. Direct messages end with @c.us.

client.onMessage(async (message) => {
  const isGroup = message.from.includes('@g.us');
  const isDirect = message.from.includes('@c.us');

  if (isGroup) {
    // Handle group message
  }

  if (isDirect) {
    // Handle direct message
  }
});

Using isGroupMsg

Some message objects include an isGroupMsg field:

client.onMessage(async (message) => {
  if (message.isGroupMsg) {
    // This is a group message
  }
});

Getting the Group ID

The group ID is the from field for group messages:

client.onMessage(async (message) => {
  if (message.from.includes('@g.us')) {
    const groupId = message.from; // e.g., "123456789-1111111@g.us"
    console.log('Message from group:', groupId);
  }
});

Configuring Which Groups to Process

Allowlist

Only process messages from specific groups:

const allowedGroups = new Set([
  '123456789-1111111@g.us',
  '987654321-2222222@g.us',
]);

client.onMessage(async (message) => {
  if (message.from.includes('@g.us') && !allowedGroups.has(message.from)) {
    return; // Skip groups not in allowlist
  }
  // Process the message
});

Blocklist

Skip specific groups:

const blockedGroups = new Set([
  '123456789-1111111@g.us',
]);

client.onMessage(async (message) => {
  if (blockedGroups.has(message.from)) {
    return; // Skip blocked groups
  }
  // Process the message
});

Exempting Admins

Getting Group Admins

const groupAdmins = await client.getGroupAdmins(groupId);

Checking if Sender is Admin

client.onMessage(async (message) => {
  if (!message.from.includes('@g.us')) return;

  const admins = await client.getGroupAdmins(message.from);
  const senderNumber = message.author?.split('@')[0];

  if (admins.includes(senderNumber)) {
    // Sender is an admin, exempt from moderation
    return;
  }

  // Process the message (e.g., moderate it)
});

Config-Based Admin Exemption

const exemptAdmins = new Set(config.adminIds || []);

client.onMessage(async (message) => {
  const senderId = message.author || message.from;
  if (exemptAdmins.has(senderId)) {
    return; // Admin messages are exempt
  }
  // Process the message
});

Group-Specific Behavior

Different Responses per Group

const groupConfig = {
  'group1@g.us': { language: 'en', moderation: true },
  'group2@g.us': { language: 'es', moderation: false },
};

client.onMessage(async (message) => {
  const config = groupConfig[message.from];
  if (!config) return; // Unknown group

  if (config.moderation) {
    // Apply moderation
  }
});

Group Welcome Messages

client.onMessage(async (message) => {
  if (message.type === 'gp2' && message.subtype === 'add') {
    const newMember = message.recipients?.[0];
    await client.sendText(message.from, `Welcome ${newMember}!`);
  }
});

Groups guide - Full group management
AI Agent Patterns - Group chat handling in AI agents
Example: OpenAI Moderation - Group moderation plugin

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