Free Online JSON Validator
The JSON validator parses input against RFC 8259 and reports whether it's syntactically valid, including the exact line and reason for any parse error.
Your data is processed entirely in your browser and never sent to any server.
How to Use This Developer Tool
- Paste your JSON into the input area.
- A valid badge appears when the JSON parses cleanly.
- If invalid, read the error with line and column hints below the input.
- Fix the issue at the flagged line and revalidate.
What Is a JSON Validator?
JSON's strictness is the cause of most parsing pain: trailing commas, single-quoted strings, unescaped backslashes, and unmatched braces all break the parser. Editors usually flag these only when something tries to consume the result; pasting into a dedicated validator surfaces the issue immediately with an actionable message.
Use it to debug a webhook payload that a downstream service rejected, to check that a config file you hand-edited still parses, or to confirm an LLM-generated response actually conforms before passing it to `JSON.parse`. The validator uses the browser's native parser and reports a few common structural issues (unbalanced quotes, stray characters) before the parser sees them.
Frequently Asked Questions
How does JSON validation work?
Can I validate large JSON files?
What errors does the validator catch?
Published by the WeGotEveryTool team. We build and test every tool in-house and update pages when the underlying spec, formula, or recommendation changes.
Reviewed: May 2026. Disclaimer: this tool is provided as-is for general informational use. For decisions with material consequences (medical, legal, financial, security) verify results against a qualified professional source.