Privacy policy

Practical Data, a Chrome extension. Last updated October 5, 2026.

Practical Data shades the comparable columns of tables on web pages. To decide what each column means, it asks a decision model run by a third-party provider that you choose and pay for directly. This page says exactly what that involves.

What leaves your browser

When a table comes within about a screen of the viewport on a site where the extension is on, the extension sends this to your chosen provider:

• The page title.
• The table's caption or nearest heading, and its column headers.
• A few sample values from each column, and the distinct labels in label columns (for example Lightweight, Versatile, Powerful).
• The first and last two rows, to check whether they are totals.

It does not send the page URL, cookies, form contents, text outside tables, or anything from tables you never scroll near.

Who receives it

Only the provider you configure in the extension's options:

• TypeSafe (Jev), at api.typesafe.ai, under TypeSafe's terms and privacy policy.
• Cloudflare (Clef, on Workers AI), at api.cloudflare.com, under Cloudflare's privacy policy.

The extension's author does not run a server and receives nothing: no analytics, no telemetry, no crash reports.

What is stored, and where

All in your browser's extension storage, on your device:

• Your API key or token, entered in the options. It is read only by the extension's own pages and background worker and sent only to the provider you chose. Web pages and the scripts that run on them can't read it.
• Cached model answers, so an unchanged table is not sent twice. The cache is capped; the oldest entries are evicted. Options has a button to clear it.
• Your settings: palette, mode, and the sites you turned on or off.
• For the current browser session only: pages you paused and per-table choices (rows or columns, hidden).

Your controls

• Turn a site off, or switch to Only sites I turn on so nothing is sent unless you enable a site. Do this for pages with private data.
• Pause a page from the toolbar popup or with ⌥⇧H.
• Clear cached answers in the options.
• Uninstall to remove everything the extension stored.

Sites can opt out for all users with <meta name="practical-data" content="off">.

Changes

Changes to this policy will be noted here with a new date.