Privacy policy

Last updated 27 July 2026

Plumline comes in two forms: a free online solver that runs in your browser, and a Google Sheets add-on. Neither sends your data to a Plumline server, because there is no Plumline server, no Plumline account, no analytics and no tracking. The rest of this page explains each one in full.

The online solver

The online solver at plumline.online runs entirely in your browser. The model you type is read and solved locally on your own device. When you paste a table from Excel or Google Sheets, that clipboard data is read only at the moment you paste it into the grid; it stays in browser memory and is not uploaded. The Undo snapshot of your grid is kept only in memory and is discarded when you make a new edit, undo, or reload the page. No model data is uploaded to Plumline or anyone else. It sets no cookies, runs no analytics, and needs no account. Closing or refreshing the page clears the model; nothing is stored between visits.

The Google Sheets add-on

What Plumline accesses

When you open the panel, Plumline reads the values and formulas of the active spreadsheet to work out the model and solve it. It reads nothing until you open the panel, and nothing outside the spreadsheet the add-on is installed in. It holds two authorisations from your Google Account:

• spreadsheets.currentonly, access limited to the spreadsheet the add-on is installed in. It cannot reach any other file in your Drive.
• script.container.ui, permission to display the side panel.

It requests no access to Gmail, Drive at large, Calendar or Contacts, and makes no requests to any external service.

What Plumline stores, and where

So you don't have to define your model again each time, Plumline saves its definition, which cells are the quantities, which cell is the total, and the limits, using the Apps Script document properties of that same spreadsheet. It also keeps the previous values of the quantity cells so the last write can be undone.

This stays attached to your spreadsheet, inside Google's infrastructure. It is never sent to us or anyone else, and it is removed when you use “forget this model”, uninstall the add-on, or delete the spreadsheet.

What Plumline does not do

• It does not transmit your spreadsheet contents anywhere.
• It uses no cookies, analytics, advertising or tracking.
• It creates no Plumline account and asks for no email address.
• It does not use your data to train any model.
• It shares and sells nothing, because it holds nothing to share or sell.

This website carries no analytics and loads no third-party scripts or images.

Where the processing happens

Plumline runs as a Google Apps Script bound to your spreadsheet, so the reading, the calculation and the writing all happen within Google's infrastructure under your own account. Google's handling of that data is governed by Google's privacy policy. For the add-on, Google acts as the infrastructure that runs it; no other third party is involved.

Limited use

Plumline's use of information received from Google APIs adheres to the Google API Services User Data Policy, including the Limited Use requirements. Data is used solely to provide the feature you invoked, is not transferred to others, and is not used for advertising or any purpose other than solving the model in front of you.

Your control

You can revoke Plumline's access at any time at myaccount.google.com/permissions, or by uninstalling the add-on. Because no data leaves your spreadsheet, there is nothing to request or delete from us.

Changes and contact

If this policy changes, the date at the top changes with it, and prior versions remain in this site's public history. Questions about privacy can be sent to contact@plumline.online.