JSONTech

JSON Size Analyzer

Analyze JSON data size by key — identify the largest fields in your payload

JSON Input

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Size Breakdown

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Frequently Asked Questions

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.

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.

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.

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%.