diagnostic · one of 36 free, no counter
Storage
How much is this site keeping on my machine?
Every origin keeps things on your machine, and the browser will tell you how much - it just spreads the answer across four APIs nobody opens. This gathers it into one reading: localStorage and sessionStorage measured key by key with the largest keys named, the IndexedDB databases and Cache Storage caches that exist, and the browser's own quota estimate. Sizes and names only - a value is measured and thrown away, because a size does the job and a value can be a session token.
Reach it Press ⌘ + K on any tab and type storage. Ctrl + K on Windows and Linux
in the panel · free, no counter
What this actually is
sizes, biggest keys, databases and quota — never a valueA web app that grew slow and the suspicion is a bloated cache, a privacy question about what a site leaves behind, or your own product's footprint creeping toward quota. For reading and editing an individual value, the Site data panel on the Developer tab is the surface built for that.
Asked about this diagnostic
4 of themWhy does it refuse to show values?
Because a value can be a session token, and a reading that prints one is a screen that leaks one. The footprint question - how much, where, in which keys - is answered entirely by names and sizes, so values are measured for their bytes and thrown away. A key named session_token can be listed precisely because its value never reaches the screen.
Where do I edit or delete a key, then?
The Site data panel on the Developer tab - reading and writing individual entries is its job, behind its own access grant. This screen stays a measurement so that running it never changes what it measures.
Why is the quota a question mark on some pages?
The estimate API is one the browser may withhold - private windows commonly answer with nothing - and a refusal is reported as a refusal rather than as zero. The per-store measurements above it still stand either way.
Why does IndexedDB show no databases when I know there is one?
Listing databases needs indexedDB.databases(), which not every browser answers. When it is unsupported the reading says the list cannot be read - which is a different fact from there being none, and the tool is careful not to confuse the two.
how to use storage
- Open Storage on the origin you are asking about.
- Read localStorage and sessionStorage key by key, with the largest keys named and sized.
- Read the IndexedDB databases and Cache Storage entries counted beside them.
- Compare the total against the browser's quota estimate, which it is allowed to withhold.
written about at length
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