# Backdropia — Privacy Policy

**Last updated:** July 16, 2026

Backdropia is a Chrome extension that draws a faint contour-line doodle behind AI chat sites (ChatGPT, Claude, Gemini, and others). This document explains what data the extension touches.

## TL;DR

- Backdropia operates **no server**. We do not collect, store, sell, or share any of your data.
- Everything stays on your device — including any image you upload.
- The only outbound network requests go to a small set of public, keyless sources for **source images** — **Wikimedia Commons** (`commons.wikimedia.org` / `upload.wikimedia.org`) for public-domain images (the default pool), and the open-access APIs of the **Cleveland Museum of Art** (`openaccess-api.clevelandart.org` / `openaccess-cdn.clevelandart.org`) and **The Met** (`collectionapi.metmuseum.org` / `images.metmuseum.org`) for curated CC0 artworks (the opt-in Art pool). Each source also serves as the other's fallback so the backdrop never goes blank. All are anonymous lookups — no personal data, no page content, no chat text is ever sent. The Text backdrop's words are bundled inside the extension and need no network at all.
- No telemetry, no analytics, no account, no cookies set by us.

## What data Backdropia touches

### On your device only

Backdropia uses Chrome's local extension storage (`chrome.storage.local`) to remember:

- Your preferences: on/off, mode (Ink or Color), the Visibility level, Pia's settings (shown/hidden, mood), Focus-mode state, and the backdrop type last shown.
- A cached rendering of the current doodle (the edge map produced by the on-device pipeline).
- Up to three of your most recent image uploads — the JPEG you provided and the derived edge map — along with the currently active one.
- A short rolling history of the auto-pool source images recently picked, so the picker doesn't repeat itself immediately.

Backdropia stores data using Chrome's local extension storage on your device. Backdropia itself does not operate any synchronization service.

Uploaded images remain stored locally until they are replaced by newer uploads (the library keeps the three most recent) or you uninstall the extension.

### Outbound network requests

Backdropia makes HTTPS requests only to:

- **`openaccess-api.clevelandart.org`** — the Cleveland Museum of Art's public open-access API. No API key, no account, no cookies, no identifying parameters. Used to refresh the rotating pool of curated CC0 artworks approximately once per week.
- **`openaccess-cdn.clevelandart.org`** — the actual JPEG artwork images returned by the Cleveland API.
- **`collectionapi.metmuseum.org`** — The Met's public open-access API. No API key, no account, no cookies, no identifying parameters. Also used to refresh the rotating pool of curated CC0 artworks.
- **`images.metmuseum.org`** — the actual JPEG artwork images returned by the Met API.
- **`commons.wikimedia.org`** — the public Wikimedia Commons API (`api.php`), the default image source. No API key, no account, no cookies, no identifying parameters. Refreshes a rotating pool of public-domain source images approximately once per week.
- **`upload.wikimedia.org`** — the actual JPEG image files returned by the Commons API.

These requests are governed by the respective providers' privacy policies ([Wikimedia Foundation](<https://foundation.wikimedia.org/wiki/Privacy_policy>); the Cleveland Museum of Art and The Met open-access programs). Backdropia attaches no identifying information to them beyond what your browser ordinarily sends.

The Text backdrop's words — and the short gloss shown by "what's this" — are **bundled inside the extension** and read from a local file. They add **no network requests at all**. See `THIRD-PARTY-LICENSES.md` for their sources and licenses.

### Your uploads never leave your browser

When you click the upload button and choose an image, that image is read locally, downsampled so its longest edge is ≤ 1920 px, encoded as JPEG, and stored in `chrome.storage.local`. The contour-line edge map is computed in your browser via the Canvas API. **No copy of your image is ever transmitted off-device by Backdropia.**

## Permissions

- **`storage`** — to persist your preferences and uploaded images across sessions.
- **`activeTab`** — when you click the Backdropia toolbar icon, this grants temporary access to just that one tab so the in-page control panel can be shown there. It is triggered only by your click and is never used to read or transmit page content.
- **`scripting`** — the API that injects that in-page control panel into the active tab on your toolbar click. Only Backdropia's own bundled code runs; nothing is loaded from a remote server.
- **Host permissions for supported AI chat sites** (ChatGPT, Claude, Gemini, and others; the full list is in the extension's `manifest.json`). The extension injects a Shadow-DOM-isolated visual background layer behind the site's content and is not designed to inspect, collect, or transmit page content. The optional Focus mode adds a single CSS `<style>` element to the page that fades the site's surrounding chrome (sidebars / top bar); it is purely visual, fully reversible when you turn Focus off, and reads no page content.
- **Host permissions for the Wikimedia hosts (`commons.wikimedia.org`, `upload.wikimedia.org`) and the museum image sources (`openaccess-api.clevelandart.org`, `openaccess-cdn.clevelandart.org`, `collectionapi.metmuseum.org`, `images.metmuseum.org`)** — to fetch source images for the auto-pool (Wikimedia public-domain images by default, curated CC0 museum artworks when you opt in; each is the other's fallback) as described above. These images are fetched by Backdropia's background service worker and processed on your device; no information about you, the page you're on, or your conversations is attached to the request.

## Children

Backdropia is not directed at children under 13 and collects no information from any user, regardless of age.

## Changes to this policy

If this policy changes, the updated version will replace this page and the "Last updated" date at the top will reflect the change. Material changes will also be summarized in the Chrome Web Store listing's changelog.

## Contact

Questions or concerns: **[email protected]**