23 tools
JSON Tools and Converters
JSON won as the interchange format for web APIs because it is simple enough to parse with confidence and maps directly onto the data structures every language already has: objects, arrays, strings, numbers, booleans and null. There is very little to argue about in a JSON document.
That simplicity is also its limit. There are no comments, no dates, no integers distinct from floats, and no way to express a reference from one part of a document to another. Each of those absences shows up the moment JSON is used for something it was not designed for, configuration files especially, where the lack of comments is a daily irritation.
Number handling depends on the parser, not just the JSON syntax. These browser tools use JavaScript IEEE 754 doubles, which cannot represent every integer beyond the safe-integer limit of 9,007,199,254,740,991. High-precision decimals can also round, and values beyond the finite range become null when re-serialised. JSON itself does not require all implementations to use this numeric range. Keep exact identifiers as strings when exchanging them with JavaScript consumers.
JSON tools
Converters
- CSV to JSON
Turn a CSV table into a JSON array of objects.
- JSON to CSV
Turn JSON records into a spreadsheet-ready CSV table.
- JSON to YAML
Turn JSON into readable YAML for config files and manifests.
- XML to JSON
Turn XML into JSON, with attributes and text nodes preserved.
- YAML to JSON
Turn a single YAML document into JSON, with limits on what carries over.
- JSON Lines to JSON
Wrap newline-delimited records into a JSON array.
- JSON to JSON Lines
Split a JSON array into one record per line.
- JSON to TOML
Turn JSON into TOML for Cargo, pyproject and similar config files.
- JSON to XML
Turn JSON into well-formed XML with a configurable root element.
- TOML to JSON
Turn TOML config into JSON, with dates normalised to ISO 8601.
- TSV to JSON
Turn tab-separated rows into JSON records.
- JSON to Markdown Table
Turn JSON records into an aligned Markdown table.
- Markdown Table to JSON
Turn a Markdown table into JSON records.
Formatters
Inspectors
Working with JSON
Practical guides for the tools above, including the checks to make before relying on the result.
- How to convert CSV to JSON
Convert CSV to JSON reliably: trimmed headers, type inference, empty cells, quoted fields, ragged rows and why dotted column names stay flat.
- How to format JSON
A practical guide to formatting JSON: fixing syntax errors from the line and column, choosing indentation, sorting keys, and what formatting cannot change.
- How to convert JSON to CSV
Convert JSON to CSV correctly: flattening nested objects, handling arrays and missing keys, choosing a delimiter, and the cases where CSV cannot represent the data.
- How to convert JSON to YAML
Convert JSON to YAML: review quoting, indentation, multiline values, parser-version differences and the limits of a parse-and-serialize round trip.
- How to find duplicate keys in JSON
Use the JSON Validator to find duplicate JSON keys before JSON.parse keeps only the last value, and understand the scanner limits.
- How to decode a JWT
Decode a JSON Web Token safely: the three segments, what each claim means, why decoding is not verification, and the expiry and algorithm pitfalls.
- How to convert YAML to JSON
Convert YAML to JSON with the actual parser rules: YAML 1.2 defaults, configured merge expansion, duplicate and multi-document rejection, and directives.
Worth understanding first
The concepts that come up most often when working with JSON.