JSON Formatter Guide
When API payloads are minified or messy, debugging gets slower. A JSON formatter turns raw JSON into readable structure so you can inspect data quickly.
What it is
- A JSON formatter parses JSON text and rewrites it with indentation and line breaks.
- It can also validate syntax and show parse errors before you send or store payloads.
Why developers use it
- Readable JSON reduces mistakes when checking nested objects and arrays.
- Formatted payloads are easier to share in bug reports, docs, and code reviews.
- Quick validation helps catch malformed requests before they hit an API.
Example
Before and after formatting
Input
{"user":{"id":1,"name":"John Doe","roles":["admin","editor"]}}Output
{
"user": {
"id": 1,
"name": "John Doe",
"roles": ["admin", "editor"]
}
}JSON formatting vs JSON validation
Formatting and validation are related but different:
- Formatting — adds indentation and line breaks for readability. Valid JSON only, but doesn't check your data logic.
- Validation — confirms the string is syntactically valid JSON (correct brackets, quotes, no trailing commas).
- Schema validation — checks your JSON against a defined structure (types, required fields). Requires a JSON Schema.
The apidevtools JSON Formatter does formatting + validation. For schema validation, see the JSON to JSON Schema tool.
Common JSON errors
| Error | Cause | Fix |
|---|---|---|
| Unexpected token | Trailing comma, single quotes | Use double quotes, remove trailing commas |
| Unexpected end | Missing closing bracket/brace | Check bracket pairing |
| Invalid escape | Unescaped backslash in string | Use \\ instead of \ |
| Circular reference | Object references itself | Restructure the data |
The formatter highlights the exact line where the error occurs.
How to use the tool
- Paste raw JSON into the input area.
- Click Format to beautify or Minify to compress output.
- Use Validate to confirm syntax, then copy the result.