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jsoncsvonline

1-click auto-repair

Repair and fix broken JSON syntax in real time.

Fix unquoted keys, single quotes, trailing commas, Python literals, and JavaScript comments automatically. Instant 1-click syntax repair with zero server uploads.

  • 100% in-browser processing — check the Network tab
  • Fixes unquoted keys, single quotes & commas
  • 1-click export to CSV & Excel
Spec:
Indent:
INPUT JSON Standard
Ln 1, Col 1
VALID

Capabilities

Engineered to recover broken data instantly.

Payloads exported from logs, Python scripts, or AI prompts frequently violate strict JSON standards. Our engine identifies non-standard syntax and repairs it in one click without altering your data values.

Automatic quotes & keys normalization

Turns unquoted keys like {name: "John"} into valid RFC 8259 property strings {"name": "John"} and normalizes single quotes to double quotes.

Trailing commas & comment removal

Cleans up trailing commas in objects and arrays that break strict parsers, and safely strips JavaScript line (//) and block (/* */) comments.

Python dictionary translation

Automatically translates Python str(dict) and repr() exports containing True, False, and None literals into standard JSON true, false, and null.

Programmatic Repair

How to repair non-standard JSON in code

When dealing with external APIs or legacy log files that emit non-standard JSON, here is how to sanitize and repair syntax programmatically:

JavaScript regex sanitation

// Repair single quotes and unquoted keys in JavaScript
function basicRepair(malformed) {
  return malformed
    // Replace single quotes around strings
    .replace(/'([^'\\]*(?:\\.[^'\\]*)*)'/g, '"$1"')
    // Quote unquoted object keys
    .replace(/([{,]\s*)([a-zA-Z0-9_]+)\s*:/g, '$1"$2":')
    // Remove trailing commas
    .replace(/,\s*([}\]])/g, '$1');
}

Python ast.literal_eval

# Safely parse Python dictionary strings to valid JSON
import ast
import json

python_dict_str = "{'active': True, 'owner': None, 'retries': 3,}"

# Safely evaluate literal expression without eval() risk
parsed = ast.literal_eval(python_dict_str)

# Dump as valid standard JSON
valid_json = json.dumps(parsed, indent=2)

FAQ

JSON Repair, in detail

How does this online JSON repair tool fix invalid syntax?

The repair engine uses a lenient streaming scanner to detect common syntax flaws that break strict RFC 8259 JSON parsers. It converts unquoted object keys to double-quoted strings, normalizes single quotes, eliminates trailing commas, replaces Python literals (True, False, None) with standard JSON equivalents (true, false, null), and strips JavaScript line or block comments.

Why does Python dictionary output fail in standard JSON parsers?

Python str(dict) and repr() output uses single quotes around strings and Python-specific keywords (True, False, None). Standard JSON mandates double quotes and lowercase true, false, and null. Our auto-repair tool immediately detects this pattern and converts it into valid, compliant JSON.

Can this tool fix trailing commas in JSON arrays and objects?

Yes. Trailing commas before closing braces (}) or brackets (]) are the single most common cause of JSON parsing errors. Our engine identifies and strips trailing commas automatically without modifying valid comma separators.

Does auto-repair alter the values or structure of my payload?

No. The repair algorithm strictly repairs structural syntax rules (delimiters, quotes, keywords) required for parsing. Your data fields, values, and hierarchy remain unchanged.

Can I convert repaired JSON directly to CSV or Excel?

Yes. Once repaired, you can copy or download the valid JSON, or use the direct converter shortcuts to export your structured data as CSV or Microsoft Excel spreadsheets with zero server roundtrips.

Are my malformed payloads sent to an external server to be repaired?

No. All diagnostics and automated repair logic execute locally on your machine in your browser. No file or text content is ever uploaded to any backend service.

Is my data uploaded to a server?

No. The conversion runs in a Web Worker inside this page, so the file never leaves your device. You can confirm it rather than take our word for it: open your browser devtools, switch to the Network tab, and convert something. There are no requests. This is also why there is no size cap and no daily quota — there is no server bill to ration.

Is there a file size limit?

No. Input is read in chunks and output is streamed, so memory use stays flat instead of scaling with the file. The practical ceiling is your own machine, and it is measured in gigabytes rather than megabytes. Files that large are best given as a file rather than pasted, because a browser textarea is the slowest part of the whole pipeline.

Is it free, and do I need an account?

It is free with no account, no trial and no paid tier that unlocks bigger files. Nothing about the page changes based on who you are, because the page does not know.

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