FormaX

JSON Formatter & Viewer Online Tool

Json formatter online, json viewer - Format, validate and beautify JSON data with syntax highlighting and error prompts

đź’ˇ Tip: Supports automatic parsing of JSON string formats, including nested JSON strings. For example:

  • Double quote format:"{\"name\":\"John\"}"
  • Single quote format:'{"name":"John"}'
  • Nested JSON string:{"data":"{\"age\":30}"} will be automatically parsed as {"data":{"age":30}}

Input JSON

Valid

Format Result

Syntax Validation

Real-time JSON syntax error checking with detailed error information and location prompts

Format & Beautify

Automatically format JSON data with customizable indentation size for better readability

One-Click Export

Support copy to clipboard and download files for easy saving and sharing of results

JSON Formatting, Validation, and Debugging Guide

JSON problems usually appear during API debugging, log inspection, and configuration migration. FormaX parses input in the browser, produces a readable result, and keeps the original text when syntax errors need investigation.

Use it for API responses, webhook payloads, exported configuration, and escaped JSON strings from logs. Formatting does not upload the payload to a server.

Recommended Workflow

  1. Paste the raw JSON or response body and check whether the validity indicator is green.
  2. If the text comes from logs, remove timestamps, request IDs, and outer quotes before formatting.
  3. Choose 2 or 4 spaces according to your codebase or documentation style.
  4. Before copying, verify array sizes, field casing, and null values so debug data does not leak into configuration.

Debugging Example

{"user":{"id":42,"roles":["admin","editor"]},"enabled":true}

Notes

  • JSON requires double-quoted object keys; single quotes and trailing commas are not valid JSON.
  • This tool validates syntax, not business rules such as required fields or enum values.
  • For very large JSON files, inspect a representative slice first, then process the full file locally.

FAQ

Why does the API still fail after JSON formatting succeeds?

Formatting only proves the JSON syntax is valid. The API may still require specific types, enum values, required fields, or date formats.

Can I paste sensitive data?

Formatting runs locally in the browser, but avoid handling secrets, tokens, or production user data on shared machines or screens.