WhatsApp Message Formatting

WhatsApp uses its own lightweight markup and a phone-number-based mention syntax. The host's WhatsApp adapter (Baileys) handles markdown conversion automatically, but mentions are only protocol-level mentions if you use the right syntax — otherwise they render as plain text and don't notify the recipient.

How to detect WhatsApp context

You're in a WhatsApp conversation when any of these are true:

The chat JID / platform id ends with @s.whatsapp.net (1-on-1 DM)
The chat JID / platform id ends with @g.us (group)
Your inbound message metadata has chatJid matching the above

Mentions — the important part

To tag a user so their name appears bold and clickable in WhatsApp and they get a push notification, write the @ followed by their phone number digits (no +, no spaces, no display name):

@15551234567 can you confirm?

The adapter scans your outgoing text for @<digits> (5–15 digits, optional leading + is stripped) and tells WhatsApp to render them as real mention tags.

The sender's phone JID is always in your inbound message metadata. When a user writes to you, inbound content.sender looks like [email protected]. The part before the @ is exactly what you put after @ when tagging them back.

Wrong vs right

You write	What recipients see
`@Adam can you...`	Plain text `@Adam`. No tag, no notification.
`@15551234567 can you...`	Bold/blue @Adam (or whatever name they're saved as), notification fires.
`@+15551234567 ...`	Same as above — adapter strips the `+`.

Picking who to tag

In a DM, there's no real need to tag the recipient (they already see every message), but tagging still works if you want emphasis.
In a group, look at the participants / inbound content.sender to find the JID of the person you mean. Don't guess from display names — pushNames can collide and are not reliable.
If you don't know the JID, just refer to the person by name in plain prose. Don't write @<name> — it won't tag and it will look like a tag that failed.

Text styles

WhatsApp uses single-character delimiters, not doubled like standard Markdown.

Style	Syntax	Renders as
Bold	`bold`	bold
Italic	`_italic_`	italic
Strikethrough	`~strike~`	~~strike~~
Monospace	`code`	`code`
Block monospace	```block```	preformatted block

The adapter converts standard Markdown (**bold**, [link](url), # heading) to the WhatsApp-native form automatically, so you don't have to think about it — but be aware that single asterisks become italics, not bold.

What not to do

Don't write <@U123> (that's Slack), <@!123> (Discord), or any other channel's mention syntax.
Don't paste a full JID like @[email protected] in the text — only the digits before the JID's @ go after your @.
Don't try to tag display names. WhatsApp has no display-name-based mention API.