CSV to JSON Converter

From Spreadsheet Rows to Structured JSON

CSV is the language of spreadsheets and exports; JSON is the language of APIs and applications. Moving data from one world to the other is one of the most common chores in modern work, and doing it by hand is error-prone exactly where it matters — quoted fields, embedded commas, line breaks inside cells. This converter handles the messy details properly: paste CSV text or upload a .csv file, and receive clean, pretty-printed JSON. The conversion runs entirely in your browser, so customer lists, financial exports and other sensitive tables never leave your machine.

How to Convert

1. Paste CSV into the input box, or drop a .csv / .txt file onto the upload zone.
2. The delimiter — comma, semicolon or tab — is detected automatically; override it manually if your data is unusual.
3. Keep First row is header enabled if your data starts with column names: each row becomes a JSON object with those names as keys. Disable it to get arrays of values instead.
4. Click Convert, inspect the formatted JSON, then copy it or download it as a .json file.

A Parser That Respects the Real CSV Rules

Naive converters split lines on commas and silently mangle real-world data. This one implements the actual CSV quoting rules: fields wrapped in double quotes may contain commas, semicolons and even line breaks; doubled quotes inside a quoted field ("") decode to a literal quote character; and Windows, Unix and old Mac line endings are all understood. Semicolon-delimited files — the default export format of spreadsheet software in many European locales — are detected and parsed without any configuration. The result is JSON that faithfully represents the table, not an approximation of it.

Typical Uses

• Seeding an application: turn a spreadsheet of products, users or locations into the JSON your code consumes.
• API testing: convert tabular test cases into request payloads.
• Data migration: legacy systems export CSV; modern systems import JSON — this is the bridge.
• Configuration: maintain settings comfortably in a spreadsheet, convert to JSON for deployment.
• Quick inspection: JSON's nested, labeled structure is often easier to read and diff than raw CSV.

Details That Affect Your Output

Header names become JSON keys exactly as written, so a tidy header row gives you tidy keys — trim stray spaces in the spreadsheet before exporting if you want clean property names. All values are emitted as strings by default, with an optional setting to auto-detect numbers and booleans; automatic detection is convenient but be aware of its edge cases, such as ZIP codes losing leading zeros when treated as numbers — that is precisely why the conversion is optional. Empty cells become empty strings rather than nulls, keeping row shapes consistent. With those rules stated plainly, what you see in the output panel is exactly what your application will receive, and for files in the tens of thousands of rows the conversion still completes in moments, because everything happens locally with no upload round-trip.

A final workflow note: this converter pairs naturally with its JSON to CSV sibling on this site, and round-tripping between them is a quick way to validate data integrity — convert a CSV to JSON, convert it back, and compare. Differences reveal quoting or type-conversion subtleties in your data before they reveal themselves in production, which is exactly when you want to meet them.