What is it

Well it's kind of like the Batman of notepad apps

No superpowers, nothing extraordinary on the surface, it looks like it could be a normal notepad.

But open the utility belt and there's a lot more in there than you'd expect: dual canvases that can hold two documents at once, raw HTML that actually renders, checklists you can tick, tables, SVGs.

Then, underneath all of it: nine separate thinking spaces, each one split in two, one side for the thing you're actually saying, one for everything that thought drags in behind it. The main idea and the tangent get to exist at the same time, side by side, rather than one waiting its turn while the other gets written down. Nine of those pairs, running in parallel.

Key features

  • Dual, independently resizable canvases (Primary + Secondary)
  • Stacked or side-by-side layout, switchable per tab
  • Per-canvas focus mode, hiding the other canvas entirely
  • Distraction-free interface with a clean "legal pad" aesthetic
  • Header and shortcuts toolbar can each be hidden
  • Two themes: Legal Pad and Midnight
  • Fully offline operation
  • Built-in live Markdown/HTML preview

What it's made for

It started as a fix for three specific annoyances: cleaning stray formatting characters out of text copied from an AI chat, having nowhere low-key and non-committal to dump Markdown and actually see it rendered, and getting content back out of other platforms without fighting their export function.

How it works

It runs entirely in the browser, as a single file, with nothing to install and nothing running in the background.

There's no login, because there's no account, because there's no platform, because there's no internet connection required to use it.

Everything stays on your machine in local storage, which is just a plainer way of saying: this is yours, actually yours, the file, not a session inside someone else's system.


Primary & Secondary

Primary and Secondary are labels more than they are roles. Two canvases can just as easily hold an old version and a new one, a document and its supplementary notes, or two things worked on in parallel, neither one subordinate to the other.


Markdown, and then whatever else you feel like

A plain, lightweight subset of Markdown, headings, bold, italic, code, lists, quotes, links, images, tables, plus an SVG tool and raw HTML rendering: paste a checkbox, a collapsible section, a callout, and it just works once you switch to preview.

Getting things in and out

Copy: raw Markdown, or rendered plain text via the copy button (strips formatting). Or highlight and copy by hand in Preview mode instead, that carries real formatting across, bold stays bold, headings stay headings.

Export: download or copy as Markdown or plain text. Also a fast way to strip stray asterisks and hashes out of anything pasted from an AI chat.

"Print": sends the rendered canvas to your browser's print dialogue, ready to save as a PDF. Choose Primary, Secondary, or both stacked. Clean output, no toolbar, no theme colours.


Shortcuts

  • ⌘/Ctrl + B / I / E / K Bold, italic, code, link
  • ⌘/Ctrl + 1–9 Switch tabs
  • ⌘/Ctrl + T / W New tab / close tab
  • ⌘/Ctrl + O Open a Markdown file

Every button's label is the shortcut itself, so there's nothing extra to memorise or look up.

Why this exists

What it's grown into covers more ground than the three annoyances it started as: thinking that hasn't settled yet, research notes that want a picture next to them, drafts headed somewhere else eventually, outlines, brainstorms, the kind of writing that needs a second track running alongside it. And if you're the sort of person who finds a CodePen snippet at 11pm and needs somewhere to actually test it, that too.

If TangentMD's useful to you and you'd like to see it keep growing, undo in Preview mode fixed, an actual Export as HTML, that kind of thing, a coffee genuinely helps make the time for it.

Not yet, maybe never

Heading navigation. Tab grouping. Search across tabs. Fixing the undo bug properly. Bringing back drag-to-reorder. None of these are promises, just the honest list of things that occurred to someone and didn't seem urgent enough to interrupt everything else for.

On the name: TangentMD

MD is Markdown, obviously. Underneath it, the tangent isn't treated as wandering, it's a controlled incision: isolate a thought, remove it cleanly, put it back once it's stopped bleeding all over the main document.

None of the other readings, Mostly Distilled, Manically Disorganised, Making Drafts, Memory Dump, Methodical Detour, cancel each other out. They're just what the same tool looks like depending on which hour of the process you catch it in.