JSON Size Estimator

JSON size matters for API responses, configuration files, and data storage. Raw size is the string length in bytes. Minified size removes whitespace and newlines. Gzip compression typically reduces JSON by 60–80% because of repeated keys and structure. This tool estimates all three.

Character encoding affects size: UTF-8 uses 1 byte for ASCII, 2–4 bytes for other characters. The byte count reflects the UTF-8 encoded string length.

Beyond size, the tool reports keys, values, nesting depth, and counts of arrays and objects. The largest string value (by character length) can reveal unexpectedly large fields. Key frequency analysis finds duplicate keys — in valid JSON, duplicate keys in the same object are overwritten by parsers, but the count helps understand structure.

Deep nesting can cause stack overflows in some parsers. A depth over 100 may warrant flattening or streaming.

Use minified JSON for production APIs and storage to reduce payload size. Use formatted (pretty-printed) JSON for debugging, config files in version control, and human-readable logs. This tool provides the minified version for copying. For formatting with indentation, use a JSON formatter tool.