Size Analyzer
Analyze JSON document size, complexity and performance hotspots
JSON Size Analyzer: Analyze JSON Payload Size & Structure Online
Your payload is broken down by key by this JSON size analyzer, showing exactly where the bulk is — which fields consume the most space, where duplication exists, and what can be optimized to reduce payload size. Any JSON document can be dropped in and a sorted breakdown by key with actionable optimization suggestions is provided. Also searched as "json size calculator".
Size breakdown by key
A sorted list of every key in your JSON ranked by how much space it consumes is shown. Often a single field (like a base64-encoded image or verbose metadata) accounts for 80%+ of the total size. This tells you exactly where to focus optimization efforts.
Optimization suggestions
Based on the analysis, concrete actions are suggested: unused fields can be removed, key names shortened for wire format, large values extracted into separate endpoints, or repetitive structures compressed into arrays. Each suggestion includes the estimated size savings.