What does the JSON Size Analyzer do?
A JSON size analyzer shows how big a document is when pretty-printed, minified and gzip-compressed, and which paths take the most bytes. It breaks the size down by strings, keys, numbers and structure, and points out repeated values and very long strings.
How to use the JSON Size Analyzer
- Paste your JSON. The report updates as you type.
- Compare the pretty, minified and gzip sizes.
- Read Heaviest paths to see which part of the structure takes the space. Paths such as $.items[*].description add up all items.
- Follow the suggestions, for example minifying, removing repeated values or switching a uniform list to TOON.
When it helps
- Finding why an API response is large
- Deciding if compression or pagination is worth it
- Checking payload size before sending it to an LLM
Frequently asked questions
How do I find out why my JSON is so big?
Paste it into the analyzer and read the Heaviest paths list. It adds up the bytes of each path, so a long text field repeated in a list shows up straight away.
Is the gzip size real?
Yes. It is measured with your browser's built-in gzip compression, so it matches what a web server would typically send.
Where else can I see the size?
The status bar under every tool shows size, gzip size, keys and depth. Select Analyze size there to open the full report beside the tool you are using.
How can I make JSON smaller?
Minify it, remove unused fields, avoid repeating long strings, enable gzip or Brotli on your server, and consider a compact format like TOON for lists of uniform objects sent to language models.