Why plain markdown?
6 May 2026
A Write 500 Words project is a folder of text files. That was settled early on, and the reasoning had less to do with anything technical than with how long novels take.
A novel is slow work. People spend years over theirs, sometimes a good deal longer, and they come back to it after long absences. Whatever a manuscript is committed to has to survive that kind of neglect.
What a markdown file is
A markdown file (.md) is a plain text file. Open one in TextEdit and you'll see the words exactly as they were typed. The only thing separating it from a .txt file is a small set of conventions: an asterisk either side of a word marks it italic, and a # at the start of a line marks a heading. A reader can ignore the conventions and still read the words, while an app that understands them renders them as styled text.
Every text editor on every operating system can open one, and that is likely to hold true for a long time yet.
A project is a folder of markdown files
A Write 500 Words project is a folder. Inside it are markdown files, one for every chapter and note, each a plain text file with a .md extension. Alongside them sits a small index recording how they're arranged in the sidebar: which chapters belong to Part One, which notes are inside the Research folder, which files have been moved to Cut Material. Between them, the files and that index are the entire format.
When you want to keep or move a whole project as a single tidy file, the app saves it as a .500words archive, which is a standard zip with the same plain markdown inside, readable on any computer.
Your manuscript is yours, fully, in a form you can read and back up however you like. iCloud Drive syncs the folder across your Macs because it is a folder, and Time Machine backs it up the same way. There's no export step and no separate backup command in between.
Why we keep markdown narrow
Markdown can do more than the app uses. Tables, inline images, heading IDs, footnotes with anchors, and a long tail of extensions are all part of the wider markdown ecosystem. Write 500 Words supports the parts a novel needs (headings, emphasis, lists, blockquotes) and leaves the rest alone.
There is a practical reason for that. A manuscript that ends up at an agent or a publisher gets reformatted to standard submission format on the way out. Anything beyond text and structure adds friction at that stage without helping the writing. Keeping the editor narrow keeps the file format tidy and the document portable. (There's a separate note on why the editor keeps markdown simple, if that's the part you were after.)
Freedom rather than insurance
Plain markdown is sometimes pitched as an insurance policy: keep your work in a format you can salvage when everything else goes wrong. We think about it the other way round. Your work isn't sitting inside a private database that only one app can read, it's the same plain text the rest of your computer already understands, so backups copy your project the way they copy any other folder and iCloud Drive syncs it without extra plumbing.
Any third-party backup tool you already trust will see plain text files and handle them the way it handles everything else on your Mac.