JSON Format Checker

Check whether JSON is formatted correctly before it breaks an API call.

A JSON format checker is useful when you are editing payloads manually, pasting data into test clients, or reviewing configuration files. DataConvertor checks the syntax in-browser, reports parser issues, and pretty-prints valid JSON for easier inspection.

What “format checker” usually means

Most developers searching for a format checker want more than a bare yes-or-no answer. They need to know where the JSON is invalid, whether braces or commas are missing, and whether the final payload is readable enough to copy into another tool. That is exactly the gap this page targets.

Example

Bad JSON
{ "name": "Ada", "active": true, }

Issue
Trailing comma before closing brace

How the checker helps

• Detects syntax errors from the browser parser.
• Surfaces line and column information when available.
• Highlights the failing line inside a code frame.
• Formats valid JSON for cleaner copy-and-paste workflows.