Data privacy

Private by design.

ESCPost prints receipts and labels from a website to a thermal printer attached to your own computer. The software runs on that computer, so there is no server of ours for your receipts to travel to. This page explains what that means in practice.

Your print data
stays with you

A receipt goes from the web page to the browser extension, from there to the ESCPost application on the same computer, and from there to the printer. It does not leave the computer, and we never receive it.

One computer

The extension talks only to the ESCPost application on the same computer. That address is reachable from that computer alone.

Page to extension to application to printer
The printer is reached over USB or your own network
No service of ours sits in that path

Nothing to sign up for

There is no account, no sign-up and no licence key. The application and the extension collect no telemetry and no analytics.

No account and no licence key
No usage tracking in the application
No usage tracking in the extension

What the extension keeps

Two small values, both held by your browser on your own computer: the websites you approved for printing, and the address of the local application once it has been found.

Stored in the browser's own extension storage
In Firefox the approvals are browser permissions
Nothing is uploaded anywhere

You approve each website

A website can print only after you approve it by name in the extension popup. You can remove that approval at any time, and a site you did not approve gets no printer list and no printing.

Approval is given one website at a time
Every request is checked against your approvals
Removing access stops printing at once

This website

escpost.dev is a static page with no backend of its own. What follows is everything that happens when you open it.

GitLab Pages serves the site. A web server has to see your request to answer it, and that request carries your IP address. That is the one unavoidable part, and it is handled by the hosting provider, not by us.

The page sets no cookies. It loads no fonts, scripts, images or trackers from anyone else; every file comes from this site. If you switch between the light and dark theme, that choice is saved in your browser's own local storage on your device and is never sent anywhere.

Check it
for yourself

ESCPost is open source under the Apache 2.0 licence. The application, the browser extension and the page library are all public, so you do not have to take any of this on trust.

Read the code that talks to your printer, and the code that decides which websites may print:

github.com/receiptful/escpost

Questions about privacy

Write to service@escpost.dev, or open an issue in the repository above.