JSON Minify

Example

{
  "user": {
    "id": 42,
    "name": "Ada Lovelace",
    "roles": ["admin", "editor"]
  },
  "active": true
}

{"user":{"id":42,"name":"Ada Lovelace","roles":["admin","editor"]},"active":true}

That is 28% smaller, from whitespace alone. Strings, numbers and key order are untouched: 1.10 and 19-digit IDs survive, unlike with JSON.stringify(JSON.parse(text)). See which values JSON.parse changes.

When to minify JSON

• Environment variables and CLI arguments that need JSON on a single line.
• JSON Lines / NDJSON files, where each record must be one line.
• Embedding JSON in a script tag, a data attribute or another string.
• Storage in databases, caches or logs where size adds up.

For HTTP responses, enabling gzip or Brotli compression saves far more than minifying, and most frameworks already send compact JSON by default. Minify when the JSON is stored or transferred uncompressed.

Minify JSON on the command line and in code

# jq: -c means compact output
jq -c . data.json > data.min.json

# Python
python3 -c 'import json,sys; print(json.dumps(json.load(sys.stdin), separators=(",", ":")))' < data.json

JSON.stringify(JSON.parse(text)); // no indent argument = compact

Python’s json.dumps adds a space after , and : by default; pass separators=(",", ":") for truly compact output. Need it readable again? Use the JSON formatter.

Frequently asked questions