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Expensico

CSV to JSON Converter

Convert CSV files to JSON arrays of objects using the header row as keys. Handles quotes, commas in values and Unicode. Runs locally.

Runs in your browser. Your files are processed on your device and are never uploaded.

How to use the CSV to JSON Converter

  1. Choose or drop your CSV file.
  2. Adjust the options if needed — the defaults work well for most files.
  3. Select Convert. Conversion happens instantly in your browser.
  4. Preview the result and download your JSON file.

About this CSV to JSON converter

CSV to JSON turns a spreadsheet export into data your code or API can consume directly. With a header row, each line becomes an object whose keys are the column names; without one, each line becomes an array.

How CSV to JSON conversion works

  1. The file is parsed with a standards-compliant (RFC 4180) CSV parser that understands quoted fields, embedded commas, escaped quotes and line breaks inside values.
  2. The delimiter (comma, semicolon, tab or pipe) is detected automatically.
  3. Optionally, values that are clearly numbers or booleans become JSON numbers and booleans. Values like 007 or +91… stay as strings so nothing is silently changed.

Conversion quality: Exact. Every row and value is preserved. Numbers and booleans can optionally be typed.

When to convert CSV to JSON

  • Importing spreadsheet data into a JavaScript app or API
  • Creating fixtures and mock data for tests
  • Converting exports from banks, CRMs or e-commerce platforms

Limitations to be aware of

  • Duplicate column names are made unique by appending _2, _3 so no data is overwritten.
  • Very large files (hundreds of MB) may exceed browser memory.

CSV vs JSON

CSV. CSV (comma-separated values) stores a table as plain text, one row per line. It is supported by almost every spreadsheet, database and programming language, but it has no formatting, formulas or multiple sheets.

JSON. JSON (JavaScript Object Notation) is the most common format for exchanging structured data between web services. It supports nested objects and arrays, strings, numbers, booleans and null.

This converter also accepts TSV files as input.

Frequently asked questions

What if a value contains a comma?

Properly quoted values like "Mumbai, India" are handled correctly. Unquoted commas inside a value make the file malformed, and the converter reports the affected rows.

Can I keep everything as strings?

Yes. Untick “Convert numbers and true/false” to output every value exactly as written.

Does it support semicolon-separated files?

Yes. The delimiter is detected automatically, so European-style CSVs with semicolons work too.

Are my files uploaded?

No. This tool reads and processes files directly in your web browser. Nothing is sent to Expensico's servers, and the data is discarded when you close or reload the page.