Big JSON Viewer

大きな JSON ファイルのためのブラウザ内ビューア——500 MB の JSON で動作検証済み。上限を決めるのはブラウザのメモリで、アプリではありません。検索・折りたたみ・コピーが軽快で、データは端末から離れません。

機能

• 大きな JSON ファイルのためにcanvas ベースの仮想ツリーが表示中の行だけを描画するため、JSON を一度解析できれば、スクロール・折りたたみ・検索は深さやファイルサイズに関係なく常時即応します。
• すべてローカル処理はすべてブラウザ内で完結。JSON はサーバーに送られず、ログにも残りません。
• 実用的な機能タブ式ワークスペース、キーパスのコピー、整形 / 生データ切替、検索、ダークモード、9 か国語に対応。

よくある質問

Big JSON Viewer のよくある質問。

ブログ

• Embed a JSON Snippet in Your Page with an iframeRender any JSON snippet as a collapsible tree inside an iframe on your own site. The data rides in the URL hash — gzipped and base64url-encoded — so nothing is uploaded. Here is the exact payload spec.
• Why JSON Viewers Stall on Rendering, Not ParsingMost JSON viewers freeze at 50 MB because they render millions of DOM nodes. Parse capacity is a browser-imposed ceiling we can’t fix, but the rendering bottleneck is fixable — and that’s where Big JSON Viewer wins.
• Local-Only by Design: Why a JSON Viewer Should Never See Your DataThe privacy story behind Big JSON Viewer is also the architecture: no server, no upload, no logs, no telemetry on your file contents. Here is what that looks like in practice.
• Big JSON Viewer vs jq, JSON Crack, and Chrome DevToolsA practical comparison of four very different JSON tools, with use cases where each one is actually the right choice — and the cases where each one breaks down.
• Sharing 500 MB of JSON in the Browser: Resumable Uploads and Gzip StreamingHow we share 500 MB JSON files via the user’s own Google Drive, with chunked resumable uploads, client-side gzip, abortable progress, and transparent decompression on the recipient side.
• Migrating from Vite to Next.js for SEO: What Actually Moved the NeedleWe moved Big JSON Viewer from a Vite SPA to Next.js to fix indexability. Here is what helped, what we expected to help but didn’t, and what was the framework just doing the work for us.