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Posting Messages

Posting Messages

thread.post() accepts every Chat SDK postable shape. The adapter renders it to what WhatsApp actually supports.

Text & formatting

await thread.post('plain text')
await thread.post({ markdown: '**bold** _italic_ ~~strike~~ `code` [docs](https://example.com)' })

Markdown / mdast is converted to WhatsApp markup:

MarkdownWhatsApp
**bold***bold*
_italic__italic_
~~strike~~~strike~
`code``code`
```block``````block```
[text](url)text (url) — WhatsApp has no hyperlinks
# Heading*Heading*
> quote> quote

Inbound WhatsApp markup is parsed back to mdast on message.formatted, so round-trips are symmetric.

Rich bubbles (AIRich)

Flip richMessages: true and markdown posts render through Zaileys AIRich  — Meta-AI-style bubbles with syntax-highlighted code blocks, tables, and directives:

const whatsapp = createZaileysAdapter({ session: { sessionId: 'main' }, richMessages: true })
 
await thread.post({
  markdown: ['## Daily brief', '', '```ts', 'const x = 1', '```'].join('\n'),
})

Plain-string posts are unaffected — only { markdown } and { ast } shapes go rich.

Files & attachments

await thread.post({
  markdown: 'Here is the report',
  files: [{ data: pdfBuffer, filename: 'report.pdf', mimeType: 'application/pdf' }],
})

Routing is by MIME type: image/* → image, video/* → video, audio/* → audio, everything else → document. The text becomes the caption of the first file; additional files send as follow-ups. Attachment objects (with data, fetchData, or url) work the same way — URLs are passed to Zaileys, which downloads them for you.

Streaming

No extra wiring — the SDK’s fallback streaming (post + edit) works because the adapter implements editMessage:

bot.onSubscribedMessage(async (thread) => {
  const stream = await ai.streamText({ /* … */ })
  await thread.post(stream.textStream)
})

Edit, delete, react, typing

const sent = await thread.post('Original')
await sent.edit('Fixed')            // → WhatsApp native edit
await sent.addReaction('👍')        // → native reaction
await sent.removeReaction('👍')
await sent.delete()                 // → delete for everyone
 
await thread.startTyping()          // "typing…" indicator

Editing supports text content. To edit media or send anything exotic, use native().

Cards

Cards render as native WhatsApp buttons with full onAction round-trips — they get their own page: Cards & Buttons.

Quoted replies

WhatsApp’s reply bubble is an adapter extension (the SDK has no quoting concept):

import { requireZaileysAdapter } from 'chat-adapter-zaileys'
 
bot.onSubscribedMessage(async (thread, message) => {
  const wa = requireZaileysAdapter(thread)
  await wa.reply(message, 'Got it!') // quotes the original, media supported
})
Message PayloadCards & Buttons