Tools/JSON
JSON formatter
jsonformatter.org, JSONLint, and JSON Editor Online split this job across ads, accounts, and “share a link” that uploads your payload. This page is the same bench in one tab: beautify and minify, lint with line numbers, repair JavaScript object literals, a collapsible tree, a table for arrays, JSONPath, CSV and YAML. API bodies with tokens in them should never hit someone else’s formatter.
- Beautify / minify / smart wrap (2, 3, 4 spaces or tabs)
- Validator with gutter, jump-to-error, JS-ism hints
- Repair: commas, quotes, comments, True/undefined
- Tree viewer, table, JSONPath, CSV and YAML
- JSONL, sort keys, ASCII \\u escapes, upload / download
- Duplicate-key warning — JSON.parse will not tell you
[
{
"sku": "A-1",
"qty": 3,
"price": 19.5
},
{
"sku": "B-9",
"qty": 1,
"price": 4
}
]In code
JSON.parse(text);
JSON.stringify(value, null, 2); // beautify
JSON.stringify(value); // minifyGuides
- JSON beautifier
Beautify minified JSON in the browser. 2/3/4-space or tabs, smart wrap for short arrays, sort keys. Line numbers and jump-to-error. Nothing is uploaded.
- JSON validator
Validate JSON online like JSONLint. Trailing commas, unquoted keys, single quotes, comments, duplicate keys. Payload stays in this tab.
- JSON minify
Minify JSON for logs, env vars, and embedding. Inverse of beautify. Client-side only.
- JSON repair
Fix JSON copied from JavaScript. Trailing commas, single quotes, unquoted keys, comments, True/None/undefined. Like Curious Concept’s fixer, in the browser.
- JSON viewer
Collapsible JSON tree like jsonformatter.org. Type colours, image URL preview, copy JSONPath or value. Runs locally.
- JSON to CSV
Convert a JSON array of objects to CSV in the browser. Nested values become JSON cells. Download or copy.
- JSON to YAML
Convert JSON to YAML in the browser. JSON types only — not a full YAML 1.2 emitter.
- JSONPath
Extract a slice of JSON with a simple JSONPath: dots, quoted keys, array indexes. Copy the result.
- Trailing commas
JSON does not allow trailing commas. How to spot them and fix a payload from JavaScript.
- JSONL
Validate JSON Lines (NDJSON). Each line is a separate JSON value. Used in logs and BigQuery loads.
- Unicode escapes
When JSON.stringify emits \u escapes vs raw characters. ASCII-safe payloads for old pipes.
- JSON vs JavaScript
Keys must be double-quoted. No undefined, functions, or comments. Dates become strings.
- Duplicate keys
RFC 8259 recommends unique keys. Most parsers keep the last duplicate. This tool warns.