JSON Editor Online vs Json Web Viewer

JSON Editor Online (jsoneditoronline.org) is the most established tool in this category and, on several axes, the better choice. We build the other one, so this page leads with the things it does that we cannot — all of them specific enough that you can check them in about five minutes.

Where JSON Editor Online is better

• Document size — not close. Its FAQ states it "can work with large files up to 512 MB." Our own documented target is 16 MB, and unlike theirs it is a measured figure rather than a stated one: 16 MB is the largest size at which every performance bound we set actually held under test. Either way, if your documents are in the hundreds of megabytes, use theirs.
• Four query languages to our three. It ships JSON Query, JMESPath, JSONPath-Plus, and JavaScript-with-Lodash. We ship JMESPath, JSONPath, and real jq 1.8.2 compiled to WebAssembly. If you want to write JavaScript against your document with Lodash available, it has that and we do not.
• Open from URL, and POST to URL. Theirs works, including an optional proxy for hosts that do not send CORS headers. Ours does not work at all — see below, because the reason is the interesting part.
• Cloud documents. Save a document, get a link, open it on another machine. Free for public documents, $5/mo for private ones. A tool with no server cannot offer this, and our URL-fragment share links are a substitute for one-off sharing only, not for storage.
• Its editor core is open source. svelte-jsoneditor, jsonrepair and lossless-json are MIT-licensed and embeddable in your own application. Json Web Viewer uses jsonrepair too — but our app itself is not open source, and theirs is reusable in a way ours is not.

The open-from-URL admission, in full

Json Web Viewer has an "Open from URL" menu item. On the production site it fails for every cross-origin URL, and it will keep failing. The site serves connect-src 'self' in its Content Security Policy, so the browser refuses the request before it leaves the machine. The app watches for that specific securitypolicyviolation and tells you the truth — "this build doesn't allow loading from other sites" — instead of blaming the remote server, but a clear error is still an error.

We are not going to widen the policy to fix it. That directive is the entire privacy guarantee (the security page explains how to verify it), and a tool that can fetch an arbitrary URL is a tool that can send your document to one. JSON Editor Online made the opposite trade and got a working feature out of it. That is a real advantage for them and a real cost for us; it is on this page because a comparison that omitted it would be dishonest.

Where Json Web Viewer is better

• Views it doesn't have. JSON Editor Online offers text, tree and table. This app adds a node-link graph, a Miller-column drill-down browser, generated type definitions (TypeScript, Go, Rust), and a HAR viewer that reads a browser network capture and diffs two of them.
• Schema generation, not just validation. Both validate a document against a JSON Schema. This app also infers a schema from a document, generates mock data from a schema, and — the part we have not seen anywhere else — generates a schema for a single selected node from the tree's right-click menu, rather than only for the whole document.
• "Across all records." Select a field inside an array of objects and the node inspector shows how that field behaves across every sibling record: distinct values, how often each occurs, how many are null. It is the fastest way we know to answer "is this field always present?" about an API response you have never seen before.
• More conversion formats. Both do CSV. This app also reads and writes YAML, XML, TOML and NDJSON, and exports a real .xlsx workbook.
• No ads, and no tier at all. JSON Editor Online shows ads on the free tier and charges $2/mo to remove them. Everything here is free and ad-free today. Worth saying plainly: that is a current posture, not a permanent guarantee — but there is nothing paywalled to discover later either.
• The privacy claim is enforced rather than scoped. Their FAQ says, in their own words, that public cloud documents are "publicly accessible for anyone who has the document id, so make sure you do not save documents with sensitive information in the cloud" — an honest warning, and one that only exists because there is a server. Here the answer has no "unless": connect-src 'self' means the browser will not connect anywhere else, and you can confirm that in DevTools in about a minute.

Things that are a wash

Both tools format, smart-format (compact-but-readable), minify, validate with click-to-jump error positions, and auto-repair with the same jsonrepair library. Both do a data-level diff that ignores key order rather than a text diff. Both run two panels side by side with copy-across and transform-across buttons between them, and both build a transform from dropdowns by analysing the document's own structure. Both offer a lossless number parser that preserves 18800000000000000123 and 4.0 exactly — theirs switches to it automatically under 10 MB, ours under 1 MB, both configurable. Both work offline after a first visit. Both are free for everything most people do.

Which one should you use

Use JSON Editor Online if your documents are very large, you want JSONPath or Lodash-flavoured JavaScript queries, you need to pull documents from a URL, or you want a document saved in the cloud and reachable from another machine.

Use Json Web Viewer if you want graph, Miller-column, type-definition or HAR views alongside the usual three; if you want to generate a schema rather than only check against one; if you want more conversion formats; or if the document you are about to paste is one you would rather not paste into anything whose privacy claim has an "unless" in it.

Other comparisons: JSON Crack · json.site · all four side by side. Or open the editor and try it against whatever you already use.