A quiet place to write.

Go ahead, type in it. The page marks English the way Stropha does, and nothing leaves your browser.

Stropha’s window in its light colours: the Library with the folder Travel open, and the document Harbour visit. — Stropha on macOS: the Library on the left, your text on the right.

Day or night. Stropha follows your system’s light or dark appearance, unless you choose one.
Your fonts. IBM Plex Sans by default, Plex Serif, Plex Mono or any font you have installed. Code can have one of its own.
Code in colour. Coloured by its language (off by default in Markdown files). Source code files open too, with line numbers, in about 200 languages.
Every command by name. The Command Palette runs any command by its name. In Stropha, ⇧⌘O opens Quick Search, which finds headings, lines and files.

Everything else can wait.

Focus Mode keeps the sentence you are writing in full ink, and the rest steps back. Put the caret anywhere in the text below, and the focus follows it.

Say it plainly.

In English, German, French and Spanish, and with patterns of your own.Parts of Speech reads English.

Your words stay yours.

Stropha keeps apart what you write, what an AI writes and what you quote. It records this in the file itself, in the open Markdown Annotations format.

Your files, where you keep them.

Add any folder to the Library. Stropha shows the Markdown files in it as they are, with favorites, smart folders and hashtags.

1 file of 6 in an example Library

Market dayTravel
Fish on ice, bread still warm, and a man selling string by the metre. The gulls watched from the roof. #travel

Let it stand.

Proofreaders write stet beside words that must stay as they were. Stropha does the same for yours.

It saves as you go. When another app changes the file, Stropha shows that version and keeps your unsaved words in Backups.
Earlier versions wait in Backups while you work.
Stropha saves a second after you pause, and while you type, it updates a copy of your words every two seconds. If your computer suddenly shuts down, they come back when you open Stropha again.

Ready to be read.

Write in plain Markdown. The Preview shows the page as readers will see it, beside the text or in its place.

# Harbour visit

The boats came in **before six**. By noon, the market was empty.

- Fish on ice
- Gulls on the roof

> Nobody counts the gulls.

```mermaid
flowchart LR
  Boats --> Market
  Boats -.-> Gulls
```

/Tides.csv

Harbour visit

The boats came in before six. By noon, the market was empty.

Fish on ice
Gulls on the roof

Nobody counts the gulls.

Tide	Time	Height
High water	11:42	4.6 m
Low water	17:58	0.9 m

PDF. Pages to read or print, with a title page, headers and footers when you want them. Diagrams stay sharp at any zoom.
Word. A document to go on editing, with its styles, tables and footnotes. Diagrams go in as pictures.
HTML. A single web page that looks like the Preview, with its pictures inside.

HTML, too.

Put HTML in your Markdown, or open a web page. The Preview lays it out as a browser would.

Stropha’s window in its dark colours: on the left, a Markdown file written in HTML, its tags and style sheet in grey; on the right, its Preview, a light web page headed “Good things start with a simple hello.” — Stropha on macOS: a Markdown file written in HTML, beside its Preview.

Laid out in the app, with no network. The HTML and CSS engine is written in Rust and runs inside Stropha. Pictures, style sheets and fonts come only from the file and its Library folder.
Web pages too. .html files open from the Library, which searches the words they show.

The same engine, for agents.

A command-line tool and an MCP server run the same engine as the app. An agent can open, read, edit and format a document, and the words it adds can be credited to AI.

$ claude mcp add stropha -- stropha-cli mcp

open_document{path: "~/Notes/Harbour visit.md"}
get_text{}
select{start: 120}
run_command{id: "authors.pasteAs", params: {kind: "ai", name: "Claude", text: " The tide turned at noon."}}
save_document{}

Harbour visit.mdSaved

# Harbour visit

The boats came in before six. By the time the market opened, the gulls had taken the best of the catch. The tide turned at noon.

An example session, in Stropha’s dark colours.

Coming soon.

For macOS, Windows and Linux.