Why doesn’t asterisk bold text work in every app on iPhone?
Wrapping a word in *asterisks* makes it bold in WhatsApp and does nothing in iMessage — same phone, same keyboard, same characters. Three unrelated mechanisms all produce something that looks like bold text, and only one of them is under your control everywhere.
Type *urgent* into a WhatsApp chat and it arrives as urgent, properly bold, the asterisks gone. Type the exact same three characters either side of the same word into an iMessage thread, or an Instagram caption, or a Notes reminder, and nothing happens — the asterisks just sit there next to the word, plain text, doing nothing. Same iPhone, same keyboard, same six characters typed in the same order. What changed was not the phone. It was which app the text landed in.
Three unrelated things that all end up looking like bold
iOS text fields have no bold button of their own, so “bold” on a phone always arrives by one of three completely separate routes, and they do not share any code, any permission, or any rule. Knowing which one an app is using is the difference between a trick that works everywhere and one that only works in the one app you learned it in.
Route one: an app parsing your punctuation on purpose
WhatsApp does not make asterisks bold by magic. Its own message composer watches for a small set of marker characters as you type or paste, and if it sees a word wrapped in single asterisks it swaps that stretch of text for a real bold style the instant it renders the message — on your screen as you type it, and again on the recipient’s screen when it arrives. The asterisks themselves are never actually part of the bold text; they are markers the app strips out once it has done the swap. Underscores do the same job for italic, and a tilde on each side does it for strikethrough.
Slack uses the identical convention — single asterisks for bold, single underscores for italic — which is not a coincidence so much as both apps drawing on the same lightweight “Markdown” formatting style that has been common in chat and developer tools for years. Discord looks similar at a glance and is not the same rule: it takes two asterisks on each side for bold, `**like this**`, and reserves a single asterisk for italic instead. Paste a WhatsApp-style bold message into Discord and it renders as italic with a stray asterisk hanging off each end, because Discord’s parser is reading the same punctuation against a different rulebook.
None of this touches iOS, the keyboard, or Full Access at all. It happens entirely inside the receiving app, after the text has already left the keyboard as perfectly ordinary characters. Apple’s own keyboard produces the identical asterisks a third-party keyboard would; what differs is only whether the app you pasted them into bothers to look for that pattern before showing them to you.
Route two: real formatting, but only inside apps built to store it
A handful of apps — Notes and Pages among them — give you an actual Bold button: select some text, tap the Aa formatting icon, and the app attaches a real style to that stretch of text, the same idea as bold in a word processor. This is genuine rich text, not a character trick, and it is why it looks identical to real bold everywhere it is used. The catch is that a message, a caption, or a bio field is just a string of plain characters with no formatting layer sitting underneath it — there is nowhere for that style to attach. Copy bold text out of Notes and paste it into an ordinary text field and the style falls away; what lands is the plain word underneath, because the field it landed in was never built to hold a style in the first place.
Route three: a different character, not a style
The one route that survives every app equally is not really “bold” in the formatting sense at all — it is a swap to a separate set of Unicode characters that already look bold: 𝗯𝗼𝗹𝗱 instead of bold, letter for letter. Because it is a real, different character rather than an instruction attached to an ordinary one, no app needs to recognise any special syntax to display it correctly. It works in WhatsApp, iMessage, Instagram captions, Discord, Slack and anywhere else plain text is accepted, without needing that app’s parser to know anything about it, and without needing markdown syntax that varies from one app to the next. The trade-off, covered in the full guide to typing bold text on iPhone, is that it is invisible to search and reads strangely to a screen reader, since as far as the phone is concerned it is not “bold Helvetica” — it is a completely different letter that simply happens to be drawn thick.
Why iOS never settled this itself
iOS gives every app the same plain, unstyled text field and leaves it up to that app’s own code to decide what, if anything, to do with the characters inside it. Some apps choose to watch for asterisks. Some build a real formatting layer for the fields they control. Most do neither and simply show you back exactly what you typed. There is no inconsistency to fix here, because there is no single shared system to begin with — a phone-wide “bold everywhere” button was never going to be possible while each app is free to render the same string of characters however it wants.
Where Kibo fits
Kibo puts route three directly on the keyboard: Bold sits among its fancy text styles, applied as you type rather than through a web generator or a round trip to another app. Because it works by swapping in the real bold Unicode characters rather than by hoping the app you are typing into understands asterisks, it reads as bold in WhatsApp, iMessage, Instagram and Discord alike, with nothing app-specific to remember. It works with Full Access left off, since fancy text is generated on the keyboard itself and never touches the clipboard.
Frequently asked questions
Why did my bold WhatsApp message show up as plain text with asterisks when I forwarded it to iMessage?
WhatsApp turns *word* into bold text itself, at the moment it renders the message — it is not sending you a bold character, it is sending plain asterisks and interpreting them as it displays them. Forward that same plain text into an app that does not look for asterisks, like iMessage, and there is nothing left to strip them out, so they show up exactly as typed.
Does Discord use the same asterisk rule as WhatsApp and Slack?
No. WhatsApp and Slack read a single asterisk on each side as bold. Discord reserves a single asterisk for italic and needs two asterisks on each side, `**like this**`, for bold. Pasting one app’s formatting into the other renders as the wrong style with stray punctuation left over.
Is there a way to make bold text that works in literally any app?
Yes — Unicode fancy text bold, a genuinely different set of characters that already look bold rather than a style layered on top of ordinary ones. Because it is plain text underneath, it displays correctly in any app without that app needing to understand any markdown syntax, though it will not be picked up by search or read naturally by a screen reader.
Try it on your own keyboard
Kibo is a free custom keyboard for iPhone with real mechanical key sounds, a wardrobe of themes and RGB backlight effects. No account, no ads, and it works with Full Access left off.