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Rescue malformed LLM JSON — truncated, trailing commas, fences.
{
"user": "Ada",
"age": 36,
"tags": [
"math",
"pioneer"
]
}Handles the classic LLM failure modes: markdown fences, trailing commas, single quotes, bare keys, smart quotes, and truncated output from token limits. Deeply malformed input fails loudly with the parser position instead of guessing.
Models emit markdown fences around JSON, forget closing brackets when hitting token limits, or lapse into Python habits (single quotes, trailing commas). Each failure mode has a deterministic fix — this tool applies them in order and logs every change.
Fence stripping, outer-text trimming, smart quotes, bare keys, single-quoted strings, trailing commas, undefined/NaN/Infinity literals, and truncation closure via a string-aware bracket stack.
If the payload still fails to parse after all repairs, you get the parser error with position instead of a fabricated guess. Silent wrong answers are worse than loud failures — especially for data pipelines.
After repairing, validate the shape: pipe the output through JSON Diff against an expected example, or generate a Zod schema from a known-good sample using our JSON to Zod converter.
The JSON Repair handles json repairdirectly in your browser. Paste or type your input, and the tool processes it instantly — no upload, no signup, no waiting. It's built for the moments when you need a quick transformation and don't want to leave your workflow.
Because the tool runs client-side, it's fast and private. Your text never touches a server, which makes it safe for sensitive content. The interface is keyboard-friendly and works on any device with a modern browser.
Common uses: people reach for this tool when they need to use a fix json from chatgpt output, remove trailing commas json online, repair truncated json response, or json unexpected end of input fix.
Browser-based tools like this one have a few real advantages over installed software or manual methods:
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