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Documentation Index

Fetch the complete documentation index at: https://mintlify.com/jzszdznzzl/WABotJS/llms.txt

Use this file to discover all available pages before exploring further.

WABotJS exposes all the information you need to work with media messages through fields on the Message object. You can inspect the content type and MIME type to decide how to handle each message, download the raw bytes as a Buffer with a single method call, and send any kind of media back using m.reply().

​
Detecting Media Messages

Check m.type to identify the kind of media in a message. Common type values are:
m.typeDescription
imageMessagePhoto
videoMessageVideo clip
audioMessageAudio file or voice note
documentMessageFile attachment (PDF, ZIP, etc.)
stickerMessageSticker (static or animated)
conversation / extendedTextMessagePlain text (no media)
You can also check that m.url is defined as a secondary guard — media messages always have a CDN URL, while text messages do not. 
bot.onMessage(async (m) => {
  if (m.isFromMe()) return;

  switch (m.type) {
    case 'imageMessage':
      console.log('Received an image, MIME:', m.mimetype);
      break;
    case 'videoMessage':
      console.log('Received a video, MIME:', m.mimetype);
      break;
    case 'audioMessage':
      console.log('Received audio, MIME:', m.mimetype);
      break;
    case 'documentMessage':
      console.log('Received a document, MIME:', m.mimetype);
      break;
    case 'stickerMessage':
      console.log('Received a sticker');
      break;
    default:
      // Not a media message
  }
});

​
Downloading Media

Call await m.download() to fetch the media file and receive it as a Node.js Buffer. WABotJS handles CDN URL resolution and decryption using the url, key, and path fields internally.
m.download() throws an Error with the message "this message is not a downloadable multimedia message" if m.url, m.key, or m.path are undefined. Always verify that the message is a media message before calling it.
import { writeFileSync } from 'node:fs';

bot.onMessage(async (m) => {
  if (m.isFromMe()) return;

  // Guard: only proceed for downloadable media
  if (!m.url || !m.key || !m.path) return;

  try {
    const buffer = await m.download();
    console.log(`Downloaded ${buffer.byteLength} bytes (${m.mimetype})`);

    // Example: save to disk
    const ext = m.mimetype?.split('/')[1] ?? 'bin';
    writeFileSync(`./downloads/${m.id}.${ext}`, buffer);
  } catch (err) {
    console.error('Download failed:', err);
  }
});
Check m.mimetype to distinguish between audio formats. For example, WhatsApp voice notes use audio/ogg; codecs=opus, whereas regular audio file attachments may use audio/mp4 or audio/mpeg. Use this to choose the correct file extension or decoder.

​
Sending Media

Send media back to any chat using m.reply() with the appropriate baileys.AnyMessageContent shape. Read the file into a Buffer first — from disk, a network request, or the result of m.download(). 
import { readFileSync } from 'node:fs';

bot.onCommand(async (m, prefix, name, args) => {
  if (name === 'photo') {
    const buffer = readFileSync('./assets/photo.jpg');
    await m.reply({
      image: buffer,
      caption: 'Here is the photo you requested!',
    });
  }
});

​
Media Message Fields

The following Message fields are populated for media messages and undefined for plain-text messages:
​
type
string | undefined
Baileys content-type key identifying the media kind (e.g. imageMessage, videoMessage, audioMessage, documentMessage, stickerMessage). Unwrapped through ephemeral and view-once wrappers automatically.
​
mimetype
string | undefined
MIME type reported by WhatsApp for the media file, e.g. "image/jpeg", "video/mp4", "audio/ogg; codecs=opus". Use this to pick the right file extension or processing pipeline.
​
hash
Buffer | undefined
The fileSha256 checksum of the media file as a Buffer. Useful for deduplication or integrity verification after download.
​
key
Buffer | undefined
The mediaKey Buffer used to decrypt the downloaded ciphertext. Required internally by m.download().
​
url
URL | undefined
A URL object pointing to the WhatsApp CDN location of the encrypted media file.
​
path
string | undefined
The directPath string that complements url for media resolution. Required internally by m.download().

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