How is this different from jsonlint or a regular JSON formatter?

Validators tell you WHERE the error is. They don't fix it. This tool actually rewrites the broken input into valid JSON, handling LLM-specific patterns (Python booleans, trailing commas, single quotes, code fences) that deterministic parsers can't handle.

Does it preserve my data?

Yes. The system prompt explicitly forbids renaming keys, paraphrasing values, or inventing fields. The AI only fixes syntax. If you're worried, check the visual diff that shows every line that changed.

What model powers this?

It runs on MarkdownMe's capped AI endpoint. The model can change over time; the privacy page names the current ones. We daily-cap requests to keep this free for everyone.

Will it work on truncated JSON?

Often yes — the model will close open brackets/braces sensibly. But if too much is missing, you may lose data. The closer to valid your input is, the better the output.

What about JSON inside markdown code fences from ChatGPT/Claude?

Handled — the tool strips ```json ... ``` wrappers and surrounding prose. For the dedicated case of extracting JSON from a full LLM response, use the LLM JSON Extractor tool.

AI JSON Repair (Fix Broken JSON)

Paste JSON that's almost-but-not-quite valid — from an LLM response, a log file, a half-broken config, or someone's hand-typed mess — and get back clean valid JSON with a visual diff showing exactly what changed. Handles trailing commas, unquoted keys, single quotes, Python True/False/None, JavaScript undefined, comments, surrounding prose, and markdown code fences. AI-powered and daily-capped to stay free.

AI-powered. Fixes trailing commas, unquoted keys, single quotes, Python True/False/None, code fences, and other LLM-output corruption.

Broken JSON (paste from ChatGPT, Claude, logs, anywhere)

136 / 10,000 chars

Repaired JSON

Inputs to AI tools may be used to improve MarkdownMe. Data controls

Was this rewrite usable?

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Frequently Asked Questions

How is this different from jsonlint or a regular JSON formatter?: Validators tell you WHERE the error is. They don't fix it. This tool actually rewrites the broken input into valid JSON, handling LLM-specific patterns (Python booleans, trailing commas, single quotes, code fences) that deterministic parsers can't handle.
Does it preserve my data?: Yes. The system prompt explicitly forbids renaming keys, paraphrasing values, or inventing fields. The AI only fixes syntax. If you're worried, check the visual diff that shows every line that changed.
What model powers this?: It runs on MarkdownMe's capped AI endpoint. The model can change over time; the privacy page names the current ones. We daily-cap requests to keep this free for everyone.
Will it work on truncated JSON?: Often yes — the model will close open brackets/braces sensibly. But if too much is missing, you may lose data. The closer to valid your input is, the better the output.
What about JSON inside markdown code fences from ChatGPT/Claude?: Handled — the tool strips ```json ... ``` wrappers and surrounding prose. For the dedicated case of extracting JSON from a full LLM response, use the LLM JSON Extractor tool.

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About AI JSON Repair (Fix Broken JSON)

AI-powered JSON repair. Fix trailing commas, unquoted keys, single quotes, Python True/False, code fences, and other LLM-output corruption. Paste broken JSON, get clean valid JSON. AI-powered. This AI-backed tool sends your input to MarkdownMe's capped AI endpoint to generate the result. You choose whether we keep it to improve the tools. See the privacy page. No account is required. MarkdownMe provides free, fast, and reliable Markdown tools for developers, writers, and anyone who works with Markdown.