JSONを圧縮

空白を削除してJSONを圧縮します。

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JSONを圧縮 の使い方

  1. 1フォーマット済みJSONを貼り付ける
  2. 2「JSONをミニファイ」をクリックする
  3. 3圧縮された一行JSON出力をコピーする

JSONを圧縮 について

JSONミニファイヤーは不要なすべてのホワイトスペース、インデント、改行を削除してJSONデータを圧縮し、コンパクトな一行のJSON文字列を生成します。データや構造を変更せずにファイルサイズを削減します。

JSONを圧縮の主な機能

  • Minify formatted JSON to a compact single-line string
  • Removes all unnecessary whitespace, indentation, and newlines
  • Validates JSON syntax before minifying — reports errors clearly
  • Shows original and minified size with the reduction percentage
  • One-click copy of the minified output
  • Works entirely in-browser — no server uploads
  • Handles deeply nested JSON objects and large files
  • Reverse operation available — paste in the JSON Formatter to re-beautify

対応フォーマット

入力フォーマット

フォーマット済みJSON（任意のインデント）既にミニファイ済みのJSON

出力フォーマット

ミニファイ済みJSON（一行、ホワイトスペースなし）

厳格なJSONのみ — コメント、末尾のカンマ、JSON5構文はサポートされていません。

使用例

Minify a formatted config file for production

Strip whitespace from a development config file before bundling for production.

入力

{
  "host": "localhost",
  "port": 3000,
  "debug": false
}

出力

{"host":"localhost","port":3000,"debug":false}

Compress a large API response for logging

Reduce a verbose API response to a single line for compact log storage.

入力

Formatted 4 KB JSON with nested objects and arrays

出力

Minified to 2.8 KB — 30% reduction

主な使用ケース

  • Compressing API response payloads to reduce bandwidth usage in production
  • Minifying JSON configuration files before bundling into a web application
  • Reducing file size of JSON data files served from a CDN
  • Storing compact JSON in database TEXT fields to save space
  • Preparing JSON constants for embedding in JavaScript source files
  • Comparing minified and formatted versions to detect whitespace-only differences

トラブルシューティング

Minified JSON is not smaller than expected

解決策

If your JSON contains mostly data values rather than formatting whitespace (e.g., a single large string), minification savings will be minimal. Gzip compression at the server level provides much larger reductions for transmitted payloads.

Syntax error reported on valid-looking JSON

解決策

Common issues include trailing commas after the last element, single-quoted strings, or JavaScript-style comments. JSON is strict — use double quotes for all keys and values and remove any comments.

Output is cut off in the copy textarea

解決策

Use the dedicated Copy button to copy the full minified string. Very long strings may appear truncated in the text area display but the copy action captures the entire content.

よくある質問

Does minification change the data?

No. Minification only removes whitespace characters (spaces, tabs, newlines). The data values, key names, array order, and nesting structure remain completely identical to the original.

How much does minification reduce JSON size?

The reduction depends on how much formatting whitespace the original contains. Typical 4-space-indented JSON files see 20–40% size reductions. Deeply nested structures with many indentation levels see the largest gains.

Is minified JSON harder to debug?

Yes, single-line JSON is hard to read. Always keep a formatted copy for development. Use this tool in the reverse direction (or the JSON Formatter) to re-beautify minified JSON when debugging.

Should I minify JSON myself or use Gzip?

Both are complementary. Minification reduces the raw file size, while Gzip further compresses the minified result during HTTP transfer. For static files served over HTTP, enabling Gzip compression at the server level is usually more impactful.

Can I minify JSON with comments?

No. Standard JSON does not allow comments. If your file is JSONC (JSON with Comments) or JSON5, remove the comments first before minifying. This tool follows the strict JSON specification.

Can I use this on JSON configuration files for frameworks?

Yes, as long as the file is valid JSON. Note that some tools like tsconfig.json accept JSONC (JSON with Comments). Strip the comments manually before minifying, then add them back afterward if needed.

Is my data sent to a server?

No. All processing is done locally in your browser using JSON.parse() and JSON.stringify(). Your JSON data never leaves your device.

Can I minify JSON arrays?

Yes. Both JSON objects and JSON arrays (and any valid JSON value including strings, numbers, and nested combinations) can be minified.