Quick JSON validator
Paste JSON text to check right away whether it is syntactically valid. If there is an error, the exact line and column of the problem are shown when your browser provides them.
How it works
Before sending JSON to an API, saving it to a configuration file or pasting it into another tool, it helps to quickly check that its syntax is valid. Paste your text and click "Validate": the tool tries to parse it and shows either a confirmation or the exact error message with, when possible, the line and column involved.
Why isn't the reported line always exact?
The JavaScript engine generally reports the position where it detected that something was wrong, which is not always the exact spot of the mistake. For example, a trailing comma left before a closing brace often makes the error point at the brace, while the real problem is just before it. Use the reported line as a starting point for your search, not as an absolute certainty.
Does the error message format change depending on the browser?
Yes: Chrome/Edge (V8) report a position as a character count from the start of the text, while Firefox directly reports a line and column. This tool detects the format your browser uses and automatically converts the position to a line and column when needed.
100% local processing: validation runs entirely in your browser, in native JavaScript — your JSON never leaves your device.