Athanor by arbastro
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The desktop app and the web app

They are the same app built from one code path, so drawing, chemistry and exports match exactly. The Windows app adds updates in the background, double-click to open files, the full Office and ChemDraw clipboard, offline use and an option to start with Windows. Signed in, your documents and preferences follow you between the two.

On a Mac, Ctrl is Cmd.

One app, two ways in

Athanor in the browser at athanor.arbastro.com/app and the Windows app are built from the same code. Every tool, menu, chemistry check and export is the same in both, and a file made in one opens unchanged in the other. Pick whichever suits the computer you are on.

Web app Windows app
Runs on Any modern browser: Windows, Mac, Linux, Chromebook Windows 10 and 11
Account Not needed to draw, convert or export Needed to start (free)
Updates A new version installs behind the page; a notice offers Reload, or it starts next time Downloads in the background, you choose when to restart
Open files by double-click No, use Ctrl+O or drag the file in .athanor, ChemDraw .cdx and .cdxml
Copy into Word or ChemDraw A picture, with the structure inside it for Athanor Every format Office and ChemDraw read, in one copy
Works offline Yes, after it has loaded once in that browser Yes: drawing, editing and exporting run on your computer
Start with Windows No Yes, a setting

What the Windows app adds

  • Updates on its own schedule. A new version downloads in the background and a Restart to update button appears. See Desktop app updates.
  • Files open by double-click. .athanor, .cdx and .cdxml files open in Athanor from File Explorer.
  • The full clipboard. A web page may only put a picture, HTML, SVG and text on the clipboard. The Windows app writes the clipboard itself, so one copy carries a sharp vector picture for Word, PowerPoint and Outlook, a ChemDraw structure ChemDraw pastes as chemistry, and the MDL molfile format older drawing programs read.
  • Start with Windows. Settings › General has Open when Windows starts. It is on by default. On the direct download there is also Start minimized; a Microsoft Store install starts normally.
  • Window shortcuts. Ctrl+N opens a new document. In the browser that key belongs to the browser itself, so the web app leaves it alone.

What follows you between them

Sign in to the same arbastro account in both and these follow you:

  • Documents. Every document saved on one device goes to your account a few seconds after it saves, and appears in Home on the other. Folders you file documents in follow too. You can turn this off per device in Settings › Storage.
  • Preferences. Theme, canvas or pages, and the subject you work in come from your account at every launch.

Signed out, nothing is synced: each device keeps its own documents and preferences.

Note

A document open in a live shared session is written to your account by that session, not by sync, so the two never write over each other.

Microsoft Store or direct download

Both are the same program. They differ only in how they update:

  • Direct download (Athanor-setup.exe from the download page) has its own updater, built into the app.
  • Microsoft Store installs are updated by the Store. The app still shows Restart to update when the Store has a new version ready.

On a Mac, Linux or a Chromebook there is no desktop build yet: open Athanor in your browser. It is the whole editor.

Getting startedHow to install Athanor on WindowsChoose Download for Windows on athanor.arbastro.com, run the installer and sign in with a free arbastro account. The desktop app is the same as the web app, updates itself, and opens .athanor, CDX and CDXML files by double-click.Troubleshooting and FAQDesktop app updatesThe Windows app checks for a new version a minute after it starts and every 30 minutes after that, downloads it in the background, and shows a Restart to update button. Your work is saved before it restarts. After seven days the update becomes required. Microsoft Store installs are updated by the Store.Getting startedWhere your work is savedThere is no save button. Every change is kept as you make it. Signed in, documents also sync to your arbastro account and appear on every device in Home. To send a file to someone, use Export or File › Download as .athanor.

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Last updated Nov 12, 2026