Recover copied output
Repair JSON copied from logs, chat messages or documentation where quotes and commas were damaged.
100% local · files never leave your browser
Format tool
Fix Broken JSON
Repair common broken JSON syntax such as trailing commas, missing quotes and incomplete structures in your browser.
✓ Free to use✓ No signup✓ Runs locally
48 bytes · local only
Waiting
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Processed entirely in this tab
Your input and result are not sent to JSON Hearth or stored on a server.
When to use it
What JSON Repair helps you do
The repair tool attempts to recover common machine-generated and hand-edited JSON mistakes. Always inspect the result because malformed input can be ambiguous.
Clean generated payloads
Fix common syntax defects in model output or partially generated examples before validation.
Diagnose manual edits
Create a readable candidate when a hand-edited configuration no longer parses.
How it works
JSON Repair, without the upload.
Add your data
Paste a value, open a local file or begin with the working sample.
Run the tool
The transformation executes in your browser, not on our servers.
Review the result
Check the output, then copy or download it for your next task.
Important limitations
What to check before using the result
Review required
Repair is best effort and cannot know the author's intended value when input is ambiguous.
Review required
Review and validate repaired output before using it in production or security-sensitive workflows.
Common questions
About JSON Repair
Does Fix Broken JSON upload my data?
No. Your input is processed by code running in your browser and is not sent to an application server.
Is JSON Repair free to use?
Yes. The tool is free, requires no account and can be used directly in the browser.
Will JSON repair always preserve the intended data?
No. It applies reasonable corrections, but severely malformed text may have more than one possible interpretation.
Should repaired JSON be trusted automatically?
No. Compare it with the source, run validation and review important values before use.