What happens when you launch the app
First-time online visitors land inside a live demo so you can feel the product before choosing a folder. Edits in a demo disappear on refresh. When you're ready, pick an empty folder — GalaxyBrain can clone the current demo into it, or just open the folder as a blank workspace. Returning visits re-open your most recent folder automatically.
Your folder is your workspace
Pick a folder, and that folder is your workspace. One folder, one user, no account. GalaxyBrain writes plain .jsonl files into pages/ and templates/, saves pasted images into images/, and keeps a small workspace.jsonl alongside them that records which tabs are open and at what widths. You'll also see CLAUDE.md and AGENTS.md — GalaxyBrain writes a short section between marker comments in each so AI agents know how to work with your workspace; anything outside those markers is yours to edit. You can zip the folder, back it up, or hand it to a friend. It's all just files on your disk.
Works in Chrome and Edge on desktop. To open a different folder at any point, pick Switch folder from the workspace menu. From that same menu you can also save an offline build — a single standalone HTML file that runs from file:// with no network.
Pages, blocks, items
A page has an icon, a title, a subtitle, and a body made of blocks — think of them as sections. Each block can freely mix prose, headings, bullets, checkboxes, ordered lists, embedded images, variables, and page links. You might have a Summary block, a Todos block, and a Projects block on the same page.
Titles take plain text only, with one exception: inside a template page you can drop in template placeholders ($NextNumber, $NextDay, $DateToday), which resolve to concrete values on real pages created from the template. Subtitles, by contrast, accept the full feature set — page links, meta values, bold and italic — so they're the natural home for live status lines like "68% complete" or "Owner: Jane Doe". If you try to insert a page link or a / meta value in a title and nothing happens, that's why.
Moving around
The workspace is tab-based: every open page is its own resizable column, side by side. Drag the right edge of a tab to resize it. Drag a tab itself to reorder tabs in the strip. Click the × on a tab to close it.
Clicking an inline link or a page-link item navigates the current tab to it, dropping a breadcrumb trail at the top of the tab so you can walk back up. Click any breadcrumb to jump back to that ancestor page.
Keyboard shortcuts throughout this guide are written as Cmd/Ctrl — Cmd on macOS, Ctrl on Windows and Linux:
- Cmd/Ctrl + click on a link (or on a breadcrumb) opens it in a new tab instead of navigating the current one.
- Cmd/Ctrl + K opens workspace-wide search across every page title, real or template. If the page you pick is already open in another tab, search scrolls that tab into view and flashes it rather than opening a duplicate — a handy way to find where a tab went.
The /, @, and $ menus
Three keystrokes drive most of the structured editing:
/— insert a meta value. A word count, a created-at timestamp, another page's variable, an aggregation across linked pages.@— insert an inline page link. The link renders with the target's current title, so renames propagate automatically across every reference.$— inside templates only, insert a placeholder:$NextNumber,$NextDay,$DateToday.
All three menus are keyboard-driven: arrow keys to navigate, Enter to select, Escape to dismiss. The / and @ menus filter live as you keep typing; $ is a short static list of the three placeholder types.
Editing essentials
Most structure is reachable from the keyboard. Start a line with any of these prefixes, then press Space, and the line converts in place:
#,##,###— Heading 1, 2, or 3-,*, or+— bullet1.,2., etc. — ordered list item (numbering starts at whatever you type)[]or[ ]— unchecked checkbox[x]or[X]— checked checkbox>name— a variable calledname
Type a URL or an email address followed by Space or Enter and it becomes a clickable link automatically. Pasting HTML from a browser preserves headings, bold, italic, and links. Copy an image — a screenshot, an image from a web page — and paste it into a page to embed it. (Paste is the supported path for images; dragging an image file in from your OS isn't currently handled.)
Cmd/Ctrl + B bolds the selection, Cmd/Ctrl + I italicises it. Tab and Shift + Tab increase and decrease indent inside bullets and ordered lists. Cmd/Ctrl + Z undoes, Cmd/Ctrl + Shift + Z redoes — undo history is per page, so undoing on one tab doesn't affect another.
Copy and paste between pages preserves the full structure — formatting, page links, images, and meta values all survive — so you can restructure a workspace by moving content around freely.
Variables and live values
A variable is a named cell with a formula. Formulas support arithmetic, constants, functions like sqrt, round, and log, and references to other variables or meta values. Results update automatically whenever the data they depend on changes.
Variables compose across pages. A "Projects" page can sum the cost variable across every linked project page without the project pages knowing anything about the overview. To build an aggregation like that, type / anywhere in your workspace, drill through the menu to the block of page-links you care about, pick a variable name that exists across those linked pages, then pick Count, Sum, Average, Min, or Max. The result updates live as those pages change.
If a formula can't resolve — you deleted a referenced page, a variable ends up depending on itself, a template placeholder is used on a page that isn't from a template — the result renders as a small inline error token (#NOT_FOUND, #CIRCULAR_REF, #MISSING_REF, #EMPTY) so you can see where to fix it, without interrupting your editing.
Page links, collections, and backlinks
Inline links sit inside prose — "I spoke to [Jane Doe] about [Portfolio Website]." Page-link items take up their own line and show the target page's icon, title, and subtitle — used when the link is the content: a row in a Projects list, a daily entry in a Journal index.
Any block of page-link items can be auto-sorted — by title, by created or updated time, by a metric (word count, list items, reference count, checkbox totals), or by any named variable on the linked pages. Inserting a new link drops it into the right slot; updating the sort key re-sorts the whole block. To set or change a block's rule, use its Order by menu in the small bar at the bottom of the block.
Every real page shows its linked references at the bottom — every other page in the workspace that mentions it, grouped by source.
Templates
Templates are blueprint pages with the full editing feature set, plus three placeholders that resolve when a real page is created from them: $NextNumber, $NextDay, $DateToday. A "Journal Entry" template numbers each entry automatically. A "Meeting" template stamps today's date.
To create a page from a template, use the New page dropdown at the bottom of a block — it lists every template in your workspace alongside a "Blank page" option. Picking a template clones the blueprint, resolves the placeholders, and inserts a page-link item back into the block you launched from. The block remembers your last choice, so the New page button goes straight to that template next time — fast for journal entries or numbered meetings. To create a new template, click the + next to the "Templates" header at the top of that same dropdown.
Templates don't appear in the @ page-link menu (you can't inline-link to a blueprint), and they aren't counted in backlinks. To edit a template, either press Cmd/Ctrl + K and pick it from search (templates show up alongside real pages in results), or click the small edit icon next to a template's name in the New page dropdown.
Images
Copy an image from anywhere — a screenshot, an image from a web page, another app — and paste it into a page. It drops in as its own image item where your caret was. Supported formats: PNG, JPEG, WebP, GIF, SVG.
Images are saved into an images/ folder inside your workspace folder alongside your pages. Pasting the same image onto several pages stores one copy on disk, not one per page.
Page actions
Click a page's icon to open an emoji picker (with search) and change it.
Each tab also has a small More options menu in its header with two items:
- Copy as markdown — copies the whole page's content as Markdown, useful for pasting into other apps or sharing a snapshot.
- Delete — removes the page after a confirmation prompt. Deletion is irreversible and also removes the page's local JSON file from your folder. The workspace always keeps at least one real page, so you can't delete your last one.
Offline mode
From the workspace menu, pick Offline mode to download the current app as a single HTML file (galaxybrain_offline.html). Double-click the file to open it in Chrome — core editing runs entirely offline from file://, against a folder on your computer. You can share that HTML with a friend or colleague; each person runs their own independent copy against their own folder.
From an offline build, the same menu item becomes Online mode and opens app.galaxybrain.com in a new tab.
Two things to know about running offline. Demo projects won't load — they're fetched over the network, so you'll need the hosted app to browse them. And Chrome's per-site storage is less reliable for pages running from file://, so the recent-folders list may not persist between sessions. You may sometimes need to re-pick your folder when you reopen the file.
AI agents
Point an MCP-aware tool (Claude Code, Claude Desktop, Cursor, Codex) at your workspace and it can read, search, traverse, and edit pages — through GalaxyBrain, under the same validation the editor applies to your own keystrokes. Agents go through the same gate you do.
Setup takes a few lines in your MCP config — or, if an agent is already running inside your workspace folder, you can just ask it to install the GalaxyBrain MCP for you. The CLAUDE.md and AGENTS.md files GalaxyBrain writes into your folder include the install snippet, so the agent has everything it needs to set itself up. Full install steps and the 13 tools are on the MCP docs page. Scripts and CLIs can talk to the same local server directly over the WebSocket API.
Keyboard shortcuts
A consolidated reference. Cmd/Ctrl means Cmd on macOS, Ctrl on Windows and Linux.
- Cmd/Ctrl + K — open workspace-wide search
- Cmd/Ctrl + click on a link or breadcrumb — open in a new tab
- Cmd/Ctrl + B — bold the selection
- Cmd/Ctrl + I — italicise the selection
- Cmd/Ctrl + Z — undo (per page)
- Cmd/Ctrl + Shift + Z (or Ctrl + Y) — redo
- Tab / Shift + Tab — increase / decrease indent inside bullets and lists
/— insert a meta value@— insert a page link$— insert a template placeholder (inside template pages)
Questions? Email hello@galaxybrain.com.