The editor is where you spend your time in Caliu, so it gets the most care. Each app has its own editor, built on its platform's own text technology, and all of them share one promise: what is stored is plain Markdown, and what you see is that Markdown, formatted in place as you type.
One loop, three editors
Every Caliu editor does the same three things:
- Read the note's Markdown and work out its structure: headings, lists, tasks, quotes, code, tables.
- Show that structure as formatted text, hiding the syntax until you need it.
- Write your edits back as Markdown, the same plain text any other Markdown app can read.
Opening a note never changes it. A note only changes when you edit it, so reading a note on another device never rewrites it behind your back.
On the web: ProseMirror
The web editor is built on Tiptap, which sits on top of ProseMirror, a toolkit for rich text editing in the browser used by many well-known writing tools. Code blocks are coloured with Shiki, the same highlighter many code editors use.
On iPhone, iPad, and Mac: Apple's own text system
The Apple editor is built directly on Apple's native text view (UITextView on iPhone and iPad, NSTextView on the Mac) and TextKit, the text engine behind Apple's own apps. Markdown is read with Apple's swift-markdown library, which follows the same specification GitHub uses, and written back with your original choices intact: if you wrote *italic* rather than _italic_, it stays that way.
The whole note is one continuous text view. That is what makes selection, scrolling, and editing across paragraphs feel natural. Things that are not plain text, such as tables and code blocks, are drawn as their own views laid over the text.
On Android: the platform's text field
The Android editor is built on Android's own text field, styled as you type. Markdown is read with commonmark-java and checked against the same reference as the Apple app. Hundreds of sample documents have to come out of the Android editor exactly as they went in, the same way they do on Apple devices.
Why native text matters
Text editing is one of the hardest things an app can do well. By building on each platform's own text engine instead of reinventing one, Caliu gets everything your device already knows how to do: autocorrect and spell checking, dictation, input methods for Japanese, Chinese, and Korean, screen readers such as VoiceOver and TalkBack, and the selection handles and shortcuts you are used to.
Seeing the Markdown
Whenever you want to see what is really stored, switch to source mode. It shows the raw Markdown, every # and * included, and you can edit it there too. See the article on source mode.