The web app

The browser version of Plan Markup runs the same viewer and the same markup file format as the Mac app, as a static web page. There is no server behind it and no account to sign in to. Your PDFs and markups never leave your machine.

It has two modes, and the browser you use decides which you get.

Folder mode (Chrome and Edge)

On Chrome and Edge, click Open plans folder and pick the folder that holds the bid’s plans. This uses the browser’s File System Access API, so the browser asks your permission before the page can read or write anything in that folder.

Once granted:

Every PDF in the folder shows in a sidebar. Click a sheet to open it.
Markups auto-save to a sidecar file next to each PDF, the same plan.pdf.markups.json convention the desktop app uses. Open the same folder on your Mac later and your markups are just there.
The app remembers recent folders on its landing screen and reopens the sheet you last had up. Reopening a remembered folder re-asks for permission with one click.
A Refresh button rescans the folder when new sheets land.

Folder mode is the closest thing to the desktop experience: work against a real plan folder, including one synced by Dropbox or iCloud, straight from a browser.

Single-file mode (any modern browser)

If your browser cannot write next to your files (Safari and Firefox, for example), or you just want to look at one sheet, drag a PDF anywhere onto the page, or click Open a PDF.

In this mode markups live in memory while you work. When you are done, click Download markups to save them as a JSON file. That download is a standard sidecar file: put it next to the PDF and the desktop app or folder mode picks it up. To resume in single-file mode later, drag the PDF and the JSON onto the page together and your markups load with the sheet.

What you can do in the browser

The browser app is the same viewer that embeds in Contractor Takeoff, and it covers the core of the daily workflow:

Mark up. Line, rectangle, ellipse, revision cloud, and text, with color and width controls. Select, move, restyle, and delete work like you expect, and ⌘Z / ⇧⌘Z undo and redo cover every edit.
Measure. Calibrate the scale with two clicks or pick a standard scale from the dropdown, then run length, area (with perimeter shown alongside), and count tools. Totals roll into the takeoff drawer and export as CSV, same as the Mac app.
Export the marked-up PDF. The Export PDF button downloads a flattened copy of the sheet with your markups baked in, ready to send. See Export marked-up PDFs.
Use your presets. Import the tool chest JSON you exported from the Mac app and arm presets from the toolbar, so your labels and styles stay consistent across both apps.

The Mac app is still the deeper tool. Arrows, freehand, highlighter, callouts, stamps, page operations, text search, and sheet overlay are desktop-only today.

Which mode should you use?

Use folder mode when you can. It saves automatically, handles whole plan sets, and behaves like the desktop app. Single-file mode is the fallback for other browsers and for quick one-sheet jobs.

Either way, the workflow is the same as on the Mac: calibrate scale, mark up, and measure.