The buffer

Scratch is a single window — the buffer. You summon it with a global hotkey, type into it, and dismiss it. Whatever was on screen is still on screen when you come back.

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One window, many buffers

The buffer shows one buffer at a time. The first line of the buffer doubles as its title and is shown in the header. Move between buffers with ⌘⇧] (next) and ⌘⇧[ (previous), or with a two-finger trackpad swipe.

The footer shows your position in the set, like 3 of 12.

Autosave

Every keystroke is queued and written to disk on a 500 ms debounce. Scratch also flushes when the window loses focus, when you switch buffers, and when the app quits. You can force a save with ⌘S, but you almost never need to.

If a save fails — disk full, permissions revoked — Scratch surfaces the error in a persistent toast at the bottom of the window. The text in the buffer remains intact.

Where buffers live

Buffers are individual Markdown files inside macOS application support:

~/Library/Application Support/Scratch/buffers/
  9c0c1c2e-….md
  b14d2d83-….md
  …

Each buffer is one .md file named with a UUID. You can open this folder directly: File → Reveal buffers folder, or Settings → General → Buffers → Reveal in Finder.

A few things worth knowing:

• The file content is plain Markdown. You can read or edit it with any tool.
• The maximum size of a single buffer is 5 MB. Scratch will refuse to load buffers larger than this — split them into multiple buffers.
• Your current buffer and ordering are tracked in a small state.json kept in Scratch’s app data — it stays on this Mac and does not move with the buffer folder. Don’t edit it by hand.
• Settings live in settings.json in Scratch’s app data, not in the buffer folder.

Backups and sync

Scratch does not run a sync service, but it can keep your buffers in a folder that something else syncs. In Settings → General → Buffers, use Buffer location → Choose folder… to point Scratch at a folder inside iCloud Drive, Dropbox, Syncthing, or a Git repo. When you choose a new folder Scratch asks whether to bring your existing buffers over; it copies them and leaves the originals in place. Use default returns to the built-in location.

Only the .md buffer files move. The current-buffer pointer and ordering (state.json) stay on this Mac, so each machine keeps its own place in the set.

Changes made elsewhere show up live. If a sync client or another machine creates, edits, or deletes a buffer, Scratch reflects it without reopening the buffer. If the buffer you’re looking at changes on disk while you have unsaved edits, Scratch shows a non-destructive banner — Keep mine or Use the other version — and never discards either silently.

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If the chosen folder is unreachable at launch (an ejected drive, say), Scratch falls back to the default location for that session and keeps your setting for next time.