What does the JSON Size Analyzer do?

It breaks down your JSON document by size, showing exactly which keys and values consume the most bytes. The interactive treemap visualization makes it easy to spot oversized fields, redundant data, or optimization opportunities.

How is the JSON size calculated?

Size is measured in bytes of the minified (whitespace-free) JSON representation. This reflects the actual payload size when transmitted over a network, which is what matters for API performance.

How can I reduce my JSON payload size?

After identifying the largest fields, consider: removing unused fields, shortening key names for API responses, moving large binary data (images) out of JSON into separate endpoints, paginating arrays, and using GZIP compression at the server level.

What's a typical JSON response size for good performance?

For web APIs, aim to keep responses under 100KB. Mobile-first APIs should target under 50KB. Responses over 1MB should be paginated or redesigned. Use GZIP compression, which typically reduces JSON size by 70-90%.

JSON サイズ分析

トリーマップでサイズ内訳を可視化

JSON Input

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Size Breakdown

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Find out exactly which keys make your payload heavy

Slow APIs and large databases often boil down to one or two oversized fields buried in an otherwise lean payload. A size analyzer breaks the document down by byte contribution and visualizes it as a treemap, so you can see at a glance which keys deserve attention before deciding what to trim, paginate, or move out of JSON entirely.

Use the analyzer when you need to

Diagnose a slow API response

Identify the field consuming most of the payload before you optimize, paginate, or compress.

Audit a stored document

See which keys take up the most room in a NoSQL or document-database record.

Plan a payload-shrinking effort

Prioritize the highest-impact fields to remove or compress instead of micro-optimizing small ones.

How to analyze JSON size

1
Paste the JSON document into the editor.
2
Click Analyze to break the document down by key with byte counts.
3
Hover or click the treemap to drill into the biggest contributors.

Keep going

Minify the payload

Strip whitespace as a first cheap optimization before refactoring fields.

Visualize as a graph

Switch to graph view when relationships matter more than size.

Inspect specific fields

Drill into a heavy node in tree view to decide how to slim it down.

Format before analyzing

Pretty-print the source so the labels in the analyzer match what you expect.

Common size-analysis workflows

Optimize a hot API endpoint

Identify the biggest fields and either trim, paginate, or move them out of the response body.

Audit a document database row

See which embedded subdocuments are pushing rows over storage limits.

Validate a compression strategy

Compare the breakdown before and after a refactor to confirm the savings landed where expected.

よくある質問

JSON ドキュメントをサイズ（バイト数）で分解し、どのキーや値が容量を最も消費しているかを可視化します。インタラクティブなツリーマップで、肥大化しているフィールドや冗長なデータ、最適化ポイントを素早く見つけられます。

空白を除いた minified JSON 表現のバイト数で計測します。これはネットワーク送信時の実際のペイロードサイズに近く、API パフォーマンスの観点で重要です。

まず最大のフィールドを特定し、未使用フィールドの削除、API レスポンスのキー名短縮、大きなバイナリデータ（画像など）を JSON に入れず別エンドポイントへ分離、配列のページネーション、サーバー側での GZIP 圧縮などを検討してください。

Web API では 100KB 未満を目標にすると良いことが多いです。モバイル中心の API なら 50KB 未満が目安です。1MB を超えるレスポンスはページネーションや設計見直しを推奨します。GZIP 圧縮は通常 JSON サイズを 70〜90% 程度削減できます。