Format, validate, explore and safely repair JSON in your browser. Your JSON is never sent to a server. The workbench is designed to remain responsive with large JSON documents.
Browser-local workbench
Edit, inspect and repair JSON
Your JSON is never sent to a server.
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0 characters · 0 bytes
Output
No diagnostics yet. Format or minify the document to validate it.
Repair preview
Review every proposed change. Repair never changes the original until you explicitly approve it.
Waiting for JSON
Technical guide
Format, validate and explore
Formatting parses valid JSON and serialises it with consistent whitespace. Minifying removes optional whitespace. Neither action changes values or array order. Optional sorting affects generated output only.
Tree exploration and duplicate keys
The tree provides collapsible paths, type labels, counts, search, JSONPath and JSON Pointer. Duplicate keys are scanned before parsing because ordinary parsers often retain only the final value.
Realistic large-file limits
Expensive parsing runs in a separate browser worker with a timeout. Tree rendering is bounded to protect responsiveness, but your device still needs enough memory for the source, parsed structure and output.
Diagnostics and repair
Fix syntax without losing the source
Errors include line and column details when the browser exposes a source offset. Repair analysis can propose changes for trailing commas, comments, single quotes, unquoted keys, missing punctuation, control characters and incomplete containers.
Every proposal includes a confidence level and meaning-change warning. The original input is never replaced unless you explicitly review and approve the preview, and an applied repair can be undone.
No. Formatting, validation, repair, tree exploration, files, copying and downloads remain inside your browser.
How does safe repair work?
JSON Central proposes an audited preview with confidence labels. Your original remains unchanged unless you review the warning and explicitly approve replacement.
What happens with duplicate keys?
Both locations are reported before parsing. The tool does not silently remove either value, because many parsers keep only the last occurrence.
Can very large JSON still fail?
Yes. The worker and bounded tree reduce interface freezes, but browser memory and processing time are finite. Extremely deep or large documents may be stopped or partially rendered.