json.site is the competitor we take most seriously, and the one we have been most wrong about. It is free, ad-free, has no accounts, markets the same privacy posture we do, and ships faster than anyone else in this category — it added a full graph view five days after we first reviewed it. On several concrete capabilities it is simply ahead of us.
connect-src 'self' as an HTTP header, which means the browser refuses any
connection to another origin regardless of what our JavaScript does. You can check that header
in DevTools in under a minute. A policy you can read is stronger than a policy you are told
about, but this is a difference in evidence, not a claim that they are doing something wrong.
jwv command-line tool and an MCP server for
coding agents, sharing the same core as the web app.
Both are free with no accounts, no ads and no paid tier. Both format, minify, validate and auto-repair. Both offer a tree, a table, a graph view and generated type definitions from a document. Both do a diff. Both handle nested JSON-encoded strings — their DeepParse, our Deep parse — which is the one feature of theirs we adopted outright after reviewing them. Both keep recent documents in local browser storage with no server involved.
Both products are closed source. Neither of us can offer you the audit that JSON Crack can. If reading the code is your requirement, that comparison is the relevant one, and neither of the tools on this page wins it.
One further procurement-relevant fact, stated neutrally because it is the kind of thing an enterprise reviewer checks: json.site's footer carries a Chinese ICP registration, which identifies the jurisdiction its operator is registered in. For a purely client-side tool that never transmits your document, operator jurisdiction matters far less than it would for a hosted service — no data reaches the operator either way. But it is a checkbox on some procurement forms, so it is stated here rather than omitted, without any implication drawn from it.
json.site ships every few days, and much of what is described above comes from its own public dated changelog rather than from driving the live app, because the site's splash screen resisted automated inspection when we last checked on 2026-08-12. Assume it has moved since. If something here is out of date — especially something out of date in our favour — write to contact@jsonwebviewer.com and we will fix it.
Six things concretely: a spreadsheet-grade table with column drag-reorder, column hiding, box-select-and-delete and Cartesian select/copy; Markdown and SQL export; a translated interface; user-rebindable keyboard shortcuts; a stated 100 MB size ceiling against our measured 16 MB; and one-click screenshot of the formatted text view as an image. We ship none of those.
Yes. Neither has ads, accounts or a paid tier today. json.site has no published revenue model at all; Json Web Viewer's ad-free, tier-free posture is a current choice rather than a permanent commitment, so it is fair to treat both as free-for-now rather than free-forever.
Look for a mechanism rather than a sentence. json.site markets itself as private, keeps history in local browser storage, and added a local-data privacy banner in August 2026 — we have no evidence against any of it, but it is a policy claim with no published enforcement. Json Web Viewer serves connect-src 'self' as an HTTP header, so the browser refuses connections to any other origin whatever the page's JavaScript tries to do, and you can read that header yourself in DevTools. That is a difference in what is checkable, not an accusation.
No. Ours is a virtualised grid for arrays of objects that sorts, edits cells in place, and can be switched on for a single nested array while the rest of the document stays a tree. json.site adds column drag-reordering, column hiding, box-select-and-delete and Cartesian select/copy on top of that. If you spend most of your time in the grid, theirs is the better one.
json.site states support for files up to 100 MB. Json Web Viewer's documented target is 16 MB, which is the largest size at which we measured every performance bound holding rather than the largest that opens at all. We have not independently benchmarked json.site's figure. For files well above 16 MB, do not assume our tool will be comfortable.
Other comparisons: JSON Editor Online · JSON Crack · all four side by side. Or open the editor and compare them on your own document.