How to Use
- Paste your JSON into the input box on the left (top on mobile).
- Choose the indent size (default 4 spaces), or choose Tab indentation.
- To expand arrays across multiple lines, check “Expand Array Indentation” (arrays stay on one line by default).
- To output JSONL, check “Output as JSONL”.
- Click “Format” (or press Ctrl+Enter).
- The formatted result appears on the right (bottom on mobile) — click “Copy” to copy it to the clipboard.
Supported Fuzzy Input
This tool automatically fixes the following common issues before parsing:
- Trailing commas: e.g. a
,after the last array element - Single-quoted strings: automatically converted to double quotes
- Unquoted keys: e.g.
{name: "Alice"}→{"name": "Alice"} - JavaScript-style comments: automatically strips
//single-line and/* */multi-line comments
What Is JSONL?
JSONL (JSON Lines) puts one complete JSON object per line, for example:
{"id": 1, "name": "Alice"}
{"id": 2, "name": "Bob"}Common uses: log analysis, importing large datasets, streaming API output.
Example
Input (with a trailing comma):
{
"name": "Alice",
"scores": [95, 87, 92,],
}Formatted (4-space indent, arrays stay on one line by default):
{
"name": "Alice",
"scores": [95,87,92]
}After checking “Expand Array Indentation”:
{
"name": "Alice",
"scores": [
95,
87,
92
]
}