Set up for a day with no connection

In Chrome or Edge, use the browser menu and choose to install the site as an app. On iPhone or iPad, use Share and Add to Home Screen. There is no store and no download: it is the same site in its own window, with an icon.

The offline cache holds public pages you have already visited. Opening the lessons, suites and topics you plan to work through, before you lose the connection, is the whole preparation step. A page you have never opened cannot be served offline.

For anything you really need, download the study guide rather than relying on the cache. A PDF or plain-text pack is an ordinary file on your device and needs nothing at all to read, including this site.

• Opening a new source: a search, a pasted URL, a site index, a paper lookup or a dictionary entry.
• Starting or submitting a formal practice attempt, which is scored on the server.
• Any page this browser has never loaded before.

Private matcher results, practice attempts, local project links, API responses and downloads are kept out of the cache on purpose. Your device-local data keeps using the browser's own storage rather than being copied into the service worker, which is why an installed app is no more exposed than a tab.