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CSV to JSON Converter

Convert CSV to JSON instantly in your browser – auto-detect delimiters, handle quotes and line breaks, create nested objects, and export clean JSON with zero uploads.

Updated

What is the CSV to JSON Converter?

Convert CSV to JSON in seconds — no uploads, no signup, no server. Paste any CSV, TSV, or semicolon-delimited export from Excel, Google Sheets, or a database and get clean, ready-to-use JSON instantly.

Unlike basic online converters that break on quoted commas, ignore line breaks inside fields, or send your data to the cloud, this CSV to JSON converter runs 100% in your browser. Your spreadsheet data never leaves your device.

It handles real-world CSV messiness:

  • Auto-detects delimiters — comma, semicolon, tab, or pipe
  • Full RFC 4180 support — quoted fields, escaped quotes (""), and newlines inside cells
  • Smart type detection — numbers, booleans, and nulls become proper JSON types
  • Nested objects — turn headers like user.name into { "user": { "name": ... } }
  • Header control — use first row as keys, or auto-generate col1, col2

Perfect for developers building APIs, importing data to MongoDB or Firebase, and analysts who need to convert CSV to JSON for JavaScript apps. Choose formatted or minified output, download instantly, and work offline.

Fast, private, and free — the CSV parser that actually understands Excel exports.

How it works

  1. Paste your CSV in the left editor. Works with:
  • Comma CSV: name,age
  • Semicolon CSV (Europe): name;age
  • TSV: name\tage
  • Files exported from Excel, Sheets, or databases
  1. The tool parses instantly:
  • Detects delimiter automatically or use your choice
  • Reads the first row as headers (toggle off if needed)
  • Respects quotes — "Smith, John",30 stays as one field
  • Handles line breaks inside quoted cells
  1. Choose your options:
  • Output format: JSON array (most common), JSON lines (NDJSON), or object keyed by column
  • Nesting: enable "dot notation" to convert address.city headers into nested objects
  • Type detection: convert "30" to number 30, "true" to boolean true
  • Trim values: remove extra spaces
  1. Copy or download formatted JSON for your API, or minified JSON for production.

Under the hood

  • Parser follows RFC 4180 CSV standard with streaming logic for large files
  • Type inference checks for integers, floats, booleans, null, and ISO dates without losing precision
  • Nested object builder splits headers by your chosen separator and builds deep objects safely
  • All processing is client-side using the File API — zero server uploads

Examples

Simple CSV to JSON array

Convert comma-separated values with headers to JSON objects for APIs

name,age,city
Alice,30,NYC
Bob,25,LA
[{"name":"Alice","age":30,"city":"NYC"},{"name":"Bob","age":25,"city":"LA"}]

Handle semicolons and nested keys

Parse European CSV with semicolons and create nested objects from dot notation

id;user.name;user.email
1;John;john@example.com
2;Jane;jane@example.com
[{"id":1,"user":{"name":"John","email":"john@example.com"}},{"id":2,"user":{"name":"Jane","email":"jane@example.com"}}]

TSV without headers

Convert tab-separated values and auto-generate column names

Alice	30
Bob	25
[{"col1":"Alice","col2":30},{"col1":"Bob","col2":25}]

Frequently asked questions

How do I convert CSV to JSON?

Paste your CSV text into the input. The converter auto-detects the delimiter and uses the first row as headers. JSON appears instantly on the right. Copy it or download as a .json file.

Does it handle commas inside quotes?

Yes. This is where most free tools fail. We follow the RFC 4180 standard, so "Doe, John", 30, "New York, NY" correctly parses into three fields, not five. Escaped quotes ("") and line breaks inside quotes also work.

Can it detect semicolons and tabs automatically?

Yes. It scores comma, semicolon, tab, and pipe delimiters on your first few rows and picks the most consistent one. You can override it manually for tricky files.

How do I create nested JSON from CSV?

Enable "Nested objects" and use dot notation in your headers. A CSV header user.name,user.email will output { "user": { "name": "...", "email": "..." } }. This is perfect for APIs and MongoDB documents.

Is my data uploaded to a server?

No. Everything runs locally in your browser, just like csvjson.com and other privacy-first tools. Your CSV never leaves your computer, making it safe for sensitive customer data or financial exports.

What about large CSV files?

Because it's client-side, you're limited by your browser's memory, not our servers. It comfortably handles files up to 50MB (around 500k rows). For larger files, it processes in chunks and warns you before Excel or browser limits are hit.

How are numbers and booleans handled?

With "Type detection" on (default), "30" becomes the number 30, "3.14" becomes a float, "true"/"false" become booleans, and empty cells become null. Turn it off to keep everything as strings, which is safer for IDs and zip codes.

Can I convert CSV without headers?

Yes. Toggle off "First row is header" and the tool will generate keys like col1, col2, col3. This is useful for raw exports or TSV data without column names.

What's the difference between JSON array and JSON Lines?

JSON array outputs [{...},{...}] — best for most APIs and JavaScript. JSON Lines (NDJSON) outputs one JSON object per line with no commas or brackets — best for streaming, BigQuery, and log processing.

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