100% Client-Side • Free • Zero Server Transfer

CSV to JSON Converter Online

Free CSV to JSON converter online. Turn spreadsheet, TSV or Excel-exported rows into a typed JSON array — numbers, booleans and nulls detected for you.

CSV InputInput

JSON OutputOutput

In short
To convert CSV to JSON, paste your spreadsheet rows into the left pane. The first row is read as the property keys and every following row becomes one object in a JSON array, with numeric, boolean and null values typed automatically in the output on the right.
CSV to JSON conversion reads the first row as property names and turns every following row into an object, producing an array you can feed to an API or a test fixture. JSON2X also infers types, so 42 becomes a number and true becomes a boolean rather than staying a quoted string. Parsing happens in the browser, so spreadsheets containing customer data never get uploaded.
How does type detection work?
CSV has no type system — every field is text. The parser therefore inspects each value: a field that parses cleanly as a number becomes a JSON number, true and false become booleans, and an empty field becomes null or an empty string depending on your setting. Everything else stays a string. The one case to watch is identifiers made of digits, such as zip codes or order numbers with leading zeros: as numbers they lose the leading zeros, so keep those columns as text if the zeros are significant.
Are quoted fields and embedded commas handled?
Yes. The parser implements RFC 4180 quoting rather than splitting naively on the delimiter, so "Smith, Ada" stays a single value, a doubled quote inside a quoted field ("") decodes to one quote character, and a line break inside quotes does not end the row. Files exported from Excel and Google Sheets follow these rules, which is why a naive split so often produces silently misaligned columns.
Can I rebuild nested objects from CSV?
If your headers use dot notation — user.name, user.email — the path structure is recoverable, which makes a round trip through JSON to CSV and back lossless for nested objects. A flat header set produces flat objects, which is usually what you want for a seed file. Once you have the JSON, generating a TypeScript interface from it gives you compile-time checking over data that started life in a spreadsheet.
How to use the CSV to JSON
Takes under a minute. Nothing is uploaded — every step runs in this browser tab.
  1. Paste CSV or open a file
    Put your delimited text into the left-hand input pane, including the header row. Tab- and semicolon-separated files work too.
  2. Pick the delimiter
    Choose comma, tab, semicolon, or pipe. Quoted fields containing the delimiter are handled correctly.
  3. Read the JSON array
    The right-hand pane shows one object per data row, with numeric, boolean, and empty values typed automatically.
  4. Copy or download
    Copy the array into your code, or download it as a .json file.
When to use it
  • Turning a spreadsheet a stakeholder sent you into a seed file or test fixture
  • Preparing bulk data for an API that accepts a JSON array
  • Loading exported analytics or CRM data into a JavaScript application
  • Converting a CSV database export into documents for a NoSQL store
  • Getting a quick, readable view of a wide CSV by inspecting one record as JSON
Step-by-step guides for this tool
Task-specific walkthroughs covering the most common ways this tool gets used.
CSV to JSON Converter: Parse Spreadsheets to JSON InstantlyConvert CSV spreadsheets to JSON arrays online. Auto-detects headers, infers data types, and handles quoted fields. Free, browser-only, no upload needed.Excel to JSON ConverterConvert Excel or Google Sheets data to a JSON array online. Copy your rows, paste them in, and get typed JSON with headers as keys. Nothing is uploaded.CSV to JSON Converter for Python DevelopersConvert CSV to JSON online — no Python required. Works like csv.DictReader in your browser, with type inference and delimiter detection.
Searches this page answers
  • csv to json online free
  • free csv to json converter
  • csv to json converter online
  • excel to json converter
  • excel to json online
  • tsv to json converter
  • convert csv to json array
  • spreadsheet to json converter
  • csv to json with types
  • csv to json no upload
Frequently Asked Questions
How does CSV to JSON conversion work?
The parser reads the first row as property keys, then converts each subsequent row into a JSON object, forming an array of structured objects.
Does it automatically parse numeric and boolean types?
Yes. Type auto-detection parses numeric strings (e.g. "42", "3.14") into JSON numbers and "true"/"false" into boolean literals.
Can I convert tab-delimited (TSV) or semicolon-delimited files?
Yes. Select delimiter options: comma (,), tab (\t), semicolon (;), or pipe (|).
How do I convert an Excel file to JSON?
Excel cannot be read directly, so use File → Save As → CSV (or Google Sheets → Download → CSV) and paste those rows here. The result is the same typed JSON array, and no spreadsheet ever leaves your machine.
Is my CSV data uploaded to a server?
No. Paste rows or drag a .csv file onto the page — either way parsing runs entirely in your browser tab, so customer lists, exports and financial rows never leave your machine.
Related Developer Tools
JSON to CSVExport JSON arrays to downloadable CSVJSON FormatterPrettify, validate & syntax-highlight JSONJSON to SQLGenerate CREATE TABLE & INSERT statementsJSON to YAMLConvert JSON to clean YAML and vice versa
Last reviewed  by the JSON2X Engineering Team.