Fix Invalid JSON Errors Instantly Online
Overview
Trailing commas, unquoted keys, single quotes, and missing brackets are the four most common JSON errors. The formatter pinpoints the exact line and column where parsing fails so you can fix it without scanning hundreds of lines manually. Works on minified JSON too.
How to Use This Tool
Paste your invalid JSON. The formatter immediately shows a red error banner with the line number and a description of the syntax issue. Fix the highlighted line and re-format to confirm validity.
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PDF Tool →Frequently Asked Questions
What causes most JSON parse errors?
Trailing commas after the last array item or object property cause roughly 40% of JSON errors. Single quotes instead of double quotes and unquoted property names are the next most common.
Can the tool auto-fix common JSON errors?
The formatter highlights errors and describes the fix. Auto-repair is risky because ambiguous errors like a missing bracket could be fixed in multiple valid ways that change your data structure.
My JSON is from an API response, why is it invalid?
APIs occasionally return HTML error pages or partial JSON when a request fails. Check that the status code was 200 before parsing. JSONP responses with a function wrapper also cause parse failures.