CSV to JSON Converter
Convert between data formats instantly with this csv to json converter. Transform your data for different applications and programming languages.
Features
- Instant Conversion: Transform data formats in milliseconds
- Preserve Structure: Maintains data relationships and hierarchy
- Error Handling: Clear feedback on conversion issues
- Copy Output: One-click copying of converted data
Example
Input:
``
name,age,city
John,30,NYC
Jane,25,LA
`
Output:
`
[
{"name": "John", "age": "30", "city": "NYC"},
{"name": "Jane", "age": "25", "city": "LA"}
]
`
Tips
First row is used as keys- All values are initially strings
- Empty cells become null values
How to Use
1. Paste your source data in the input area
2. Click convert to transform the data
3. Review the converted output
4. Copy or download the result
Best Practices
- Validate your source data before conversion
- Check the output for any formatting issues
- Test with a small sample before converting large files
- Keep backups of original data
CSV and JSON
CSV JSON Types Text only — everything is a string until you parse it string, number, boolean, null, object, array Comments No standard for them Not allowed — a comment makes the document invalid Good at Opens in any spreadsheet, streams row by row, tiny Unambiguous, parsed natively everywhere, no configuration Bad at No nesting, no types, and RFC 4180 is widely ignored — quoting and encoding vary by producer No comments, no dates, no integers distinct from floats, verbose for humans
What Does Not Survive the Trip
Everything in CSV is a string. 007 becomes the number 7 unless you keep it as text, TRUE may or may not become a boolean, and a leading = is a formula injection risk if the result ever returns to a spreadsheet.
Rules Worth Following
Convert once, at the boundary. Round-tripping through a lossier format repeatedly
degrades the data a little each time.
- Validate after converting, not before. The conversion is where things break.
- Keep the original. The converted copy is a derivative, not a replacement.
- Watch encoding. UTF-8 without a BOM is right for everything here; Excel writes a BOM
and some parsers choke on it.Numbers Are the Recurring Problem
A JSON number is an IEEE 754 double. Three consequences that bite in production:
Twitter hit the first one publicly: 64-bit tweet IDs arrived in JavaScript rounded, so the
API began sending an Value What happens Integers above 2⁵³ Silently lose precision — send IDs as strings Money as a float 0.1 + 0.2 = 0.30000000000000004 Leading zeros 007 is invalid JSON; "007" is a stringNaN and InfinityNot valid JSON at all alongside every id.
Keys, Order and Duplicates
Objects are formally unordered, though every JavaScript engine preserves insertion order for
string keys — with one exception: integer-like keys sort numerically and come first.
`javascript
JSON.stringify({ b: 1, 2: 2, a: 3 }); // {"2":2,"b":1,"a":3}
`
Duplicate keys are not an error in the spec, and JSON.parse` keeps the last one. Two
parsers can legitimately disagree about which value wins, which has been the basis of real
request-smuggling attacks.