Formateador y validador JSON

Pega JSON para formatear y validar, plegar/desplegar estructura, errores en tiempo real y resaltado. Totalmente en local.

Entrada

0 chars Consejo: pulsa Ctrl + Enter para beautify · Haz clic en ▼ para plegar/desplegar

Salida (resaltado)

El JSON procesado aparecerá aquí con resaltado, compatible con plegar/desplegar

JSON formatting & validation: make structure easy to read

When you receive a long JSON snippet (exported data, config fragments, log payloads), it’s easy to run into problems: hard to read, hard to search, and hard to pinpoint syntax errors. This tool turns messy JSON into a clear hierarchical view, and surfaces errors to help you verify and copy safely.

1. Why local processing?

Many online tools send your pasted content to a server. If that text contains accounts, business data, or secret fragments, it creates unnecessary risk.

LocalTools parses and formats JSON locally in your browser. Nothing is uploaded, and you can even use it offline.

2. Features

  • Beautify: Reformat minified JSON using 2-space indentation with syntax highlighting, making keys, strings, numbers, and booleans easy to scan.
  • Expand/collapse: After formatting, objects and arrays have toggles (▼/▶) to fold/unfold sections. You can also use “Expand all” / “Collapse all” for quick navigation of large JSON.
  • Strict validation: The tool validates syntax first. Common mistakes (trailing commas, missing quotes, bracket mismatch, etc.) are shown in a prominent error banner.
  • One-click copy: Copy the formatted result to clipboard without manual selection.
  • Syntax highlighting: A carefully tuned theme improves readability and reduces mistakes when inspecting data.

3. Common JSON error checks

  • Unexpected token: Often means an extra comma, a missing quote, or mismatched brackets near the error location.
  • Trailing commas: Standard JSON doesn’t allow a comma after the last element. For example, {"a":1,} is invalid.
  • Single quotes: JSON requires double quotes for keys and strings. Single quotes will fail parsing.
  • Comments: Standard JSON doesn’t support comments. Remove comments before formatting/validating.

4. FAQ

1. Where is the formatted result?

The formatted JSON appears immediately in the output panel (on mobile it’s below). Click the triangle toggles to expand/collapse, and use “Copy” to copy the result.

2. How large JSON is supported?

It depends on your device memory. A few MB is usually fine. Very large JSON (e.g., 50MB+) may cause brief slowdowns—desktop browsers are recommended.

3. Is my data really safe?

Yes. You can use this tool offline. All parsing and formatting runs locally in memory and is cleared when you close the page.

4. Why can’t it parse JSON with comments?

Because standard JSON doesn’t support comments. This tool follows the standard—remove comments first.