Result appears here after you select
{ } How to use
- Paste your JSON.
- Select Process to see the size and shape figures.
{ } How it works
JSON Size Analyzer works on the text you provide. Select Process ▸ and it runs entirely in your browser — nothing is uploaded to a server — then shows the result in the Output panel.
Input
- JSON input — paste or type your input in the left panel (use Sample for an example)
Output
TXT text — copy or download it from the Output panel.
{ } Common uses
- Find out why a payload is larger than you expected before optimising it.
- Check nesting depth against a parser or a database column that limits it.
- Compare two API responses by shape rather than by reading them.
{ } Limitations
- Bytes counts the text exactly as you pasted it, so indentation is included. Minify first if you want the shipped size.
- Keys counts every key at every depth, not just the top level, and Arrays counts arrays rather than their elements.
- Booleans and nulls are counted in neither Strings nor Numbers, so those two will not add up to the number of values.
{ } FAQ
Is my data uploaded to a server?
No. Everything runs locally in your browser — your files never leave your device.
Can I process more than one file at once?
This tool works on one input at a time.
Is this tool free?
Yes — it’s completely free and needs no sign-up.
Why does the byte count change when I reformat?
Because it measures the text, not the data. The same document with two-space indentation and minified are different sizes; the values in them are identical.