How do I open a JSON file online?

Click Paste or Open file, then the viewer renders a collapsible tree. You can also paste a URL or drag & drop a .json file; everything runs locally in your browser.

Is my JSON uploaded to a server?

No. MageKit processes JSON entirely in the browser using WebAssembly and Web Workers, so your data never leaves your device.

How can I compare two JSON files?

Use the Compare button to open the second document. The inline diff highlights adds, removes and changes; switch back to single view any time.

Do you support JSON5 and validation?

Yes. Paste JSON or JSON5 and click Format or Validate to beautify and check syntax. Schema validation is planned; basic syntax validation already works.

Can it handle large JSON files?

The editor streams content and uses a dedicated Web Worker, so typical configuration files and API payloads open quickly. Performance depends on your device and browser.

オンライン JSON ビュー/整形/差分 — アップロード不要

シングルエディター

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JSON Viewer & Diff Tool