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JSON formatter & validator
Check JSON syntax and download readable and minified versions side by side.
Input dataJSON
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JSON numbers use JavaScript precision. For identifiers or integers above 9,007,199,254,740,991, use quoted strings. Duplicate keys retain only the last value.
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JSON formatter & validator
Check JSON syntax and download readable and minified versions side by side.
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Open tool →How does this tool work?
Check JSON syntax and download readable and minified versions side by side.
Format and limits
JSON numbers use JavaScript precision. For identifiers or integers above 9,007,199,254,740,991, use quoted strings. Duplicate keys retain only the last value.
Up to 10 MB per input · 100,000 CSV rows · 30-second processing limit. Results stay in this browser for 1 hour.
Guides
Before your next conversion
Practical guides with examples, format limits and checks you can repeat.
JSON
Format JSON without losing sight of the data
Use formatting to understand structure, then check the values before importing a generated file.
JSONFind common JSON errors with a small example
Reduce the failing input and fix syntax before investigating an application-level problem.
CSVConvert CSV rows to predictable JSON objects
Treat the header, delimiter and quoting rules as part of the data format.
CSVExport JSON to CSV with explicit spreadsheet safety
Use a non-empty array of objects and review how nested values and formulas are represented.
CODECChoose URL encoding or Base64 for the right purpose
Encoding changes representation; neither operation encrypts the input.
CODECCompare file integrity with a SHA-256 checksum
Calculate the digest of the actual bytes and compare it with a trusted reference.
Frequently asked questions
Is my file uploaded to a server?
No. Tool inputs and outputs are processed in your browser. Messages sent through the contact form are separate.
Can I reopen a result?
Yes, in the browser that created it for one hour. Refresh or return to the page. A result link does not share the output with another device.
Which files are supported?
JSON and CSV tools process UTF-8 text files. SHA-256 accepts any file type. Each input must be no larger than 10 MB.
Does valid JSON mean my data is correct?
Validation checks syntax, not your application schema or the meaning of the data. Read the limits for numeric precision and duplicate keys.