Crosspost Checker ("the extension", "we", "our") is a Chrome extension that helps Reddit users find where a post has been crossposted, trace crosspost chains, and spot edits between versions of a post. This page explains what data the extension accesses, how it is used, and what is (and is not) collected or transmitted.
To detect crossposts, the extension reads the following information from Reddit pages you visit while browsing reddit.com:
This is web browsing activity limited strictly to reddit.com, and it is used only to power the extension's single, clearly described purpose: finding and displaying crosspost information for the post you are looking at. Nothing is read from any other website.
The extension uses Chrome's built-in chrome.storage API to remember your preferences between sessions. This data is stored locally in your browser profile (and synced through your own Google account if Chrome Sync is enabled on your device) — it is never sent to us.
| Data | Purpose |
|---|---|
| Theme (dark / light) | Remembers your preferred appearance |
| Auto-open, notifications, inline preview, max results, subreddit blacklist | Your configured extension settings |
| Favorited posts (URL & title) | Lets you keep track of posts you've starred |
| Recently tracked posts | Powers the toolbar badge count for the current tab |
You can clear this data at any time by removing the extension, or by clearing its storage from chrome://extensions.
The extension communicates with exactly one external service: Reddit's own public JSON API, over HTTPS. These requests are made directly from your browser to Reddit — they are never routed through, or seen by, any server we operate, because we don't operate one.
| Endpoint | Purpose |
|---|---|
reddit.com/by_id/… | Look up the post currently on screen |
reddit.com/duplicates/… | Find crossposts of that post |
reddit.com/user/…/submitted | Show a post author's other submissions (History tab) |
These are the same public endpoints Reddit's own website uses to load a page — no Reddit account credentials, cookies, or authentication tokens are read or transmitted by the extension.
The extension requests the following Chrome permissions, each used strictly for the purpose below:
| Permission | Why it's needed |
|---|---|
activeTab | Detect the Reddit post open in your active tab when you invoke the extension |
storage | Save your settings and favorites locally, as described in Section 2 |
sidePanel | Display crosspost results in Chrome's side panel |
contextMenus | Add a right-click shortcut to open the side panel |
alarms | Periodically refresh badge counts for tracked posts |
Host access to reddit.com / old.reddit.com | Read post data and detect crossposts, as described in Sections 1 and 3 |
Crosspost Checker is not directed at children and does not knowingly collect data from anyone, regardless of age, since it does not collect personal data from any user.
If this policy changes, the "Last updated" date at the top of this page will be revised accordingly. Continued use of the extension after changes are posted constitutes acceptance of the updated policy.
Questions about this policy or the extension's data handling can be sent to this email.