JSON Inspection Tools

5 tools · free · nothing uploaded

Questions about the document rather than its contents: how big it really is over the wire, what shape it has, and whether any of its numbers will survive a round trip through JavaScript. Nothing here modifies anything.

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Size analyzer Raw, minified and gzipped size, and which keys are responsible for the bulk of it. Stats Shape at a glance: key and value counts, type histogram, max depth, longest key. JWT decoder Header and claims decoded with a real expiry check. It never asks for your signing key. Number precision Find the int64 ids and decimals that silently lose digits when JavaScript parses them. Sample JSON Small public-domain JSON files, so you can try a tool without pasting your own data.

Why these run in your browser

There is no server-side processing here and no upload step: the page loads, and from then on the parsing, converting and rendering happen in this tab using your machine's CPU. That has three consequences worth knowing about. Your data stays on your machine, which matters when the JSON is a production payload with real customer records in it. There is no file-size limit imposed by us, only by how much memory your browser will give the tab. And once the page has loaded, it keeps working with the network off.

The trade is that very large documents are bounded by browser memory rather than by a beefy server — somewhere past 50 MB a textarea gets sluggish, and dropping the file in is better than pasting it. The privacy page spells out what is and is not collected.