How does the converter handle CSV headers?

The first row is treated as the header row by default, and each column name becomes a JSON key in the output. If your CSV doesn't have a header row, uncheck "Has Headers" to get raw arrays instead of keyed objects.

Does it support semicolon or tab-separated files?

Yes. The converter auto-detects comma, semicolon, tab and pipe delimiters, and you can also set the delimiter manually — useful for CSV files exported from European versions of Excel, which default to semicolons.

What happens to nested JSON when converting to CSV?

Nested objects are flattened into columns using dot notation, so `{"user":{"name":"John"}}` becomes a column named `user.name`. Only one level of nesting is flattened this way; anything deeper is kept as a JSON string inside the cell.

What does the "Infer Types" option do?

It detects the native type of each field instead of leaving everything as a string — `42` becomes a number, `true`/`false` become booleans, and empty fields become `null`. This is useful when the JSON is headed for an API or database that enforces strict types.

Is it safe to convert sensitive CSV or JSON data with this tool?

Yes — the conversion runs entirely in your browser using JavaScript. Your file is never uploaded or sent to a server, so it's safe to use with private spreadsheets, customer data or internal API responses.

CSV ↔ JSON Converter

Convert CSV to JSON or JSON to CSV instantly in your browser. Paste your data, choose the direction, and download the result. Free, private, no signup.

Updated April 2026

Shift + Enter to Copy

Delimiter

detected: comma

Has Headers

Output

Infer Types

CSV Input

JSON Output

[
  {
    "id": "1",
    "name": "John Doe",
    "email": "john@example.com",
    "role": "Admin"
  },
  {
    "id": "2",
    "name": "Jane Smith",
    "email": "jane@example.com",
    "role": "Editor"
  },
  {
    "id": "3",
    "name": "Bob Wilson",
    "email": "bob@example.com",
    "role": "User"
  }
]

20 lines · 308 chars

How to convert CSV to JSON

One converter, two directions — CSV to JSON or JSON to CSV

1. Pick a direction

Switch between CSV → JSON and JSON → CSV with the toggle at the top.

2. Paste or upload your file

Paste data directly, or upload a `.csv`, `.tsv` or `.json` file from your computer.

3. Configure and export

Set delimiter, headers, output format and type inference, then copy or download the result.

What this CSV to JSON converter does

Real-world CSV quirks, handled automatically

Automatic delimiter detection

Comma, semicolon, tab or pipe are recognized without any manual setup.

Quoted fields handled correctly

Commas and line breaks inside quoted CSV fields don't break the parsing.

Optional type inference

Turns "42" into the number 42 and "true" into a boolean, when enabled.

Nested JSON flattening

{"user":{"name":"John"}} becomes the user.name column when converting JSON to CSV.

Examples

What goes in, what comes out

Input

Output

CSV: `name,age\nJohn,30`

JSON: `{"name":"John","age":"30"}`

JSON: `{"user":{"name":"John"}}`

CSV column: `user.name`

Infer Types on: `"42"`

JSON: `42` (number, not string)

When you'll reach for this tool

The most common scenarios people use it for

Feed spreadsheet data into a REST API

Convert CSV to JSON to import records into MongoDB, Firestore or any JavaScript app.

Export an API response to Excel

Convert JSON to CSV to share structured data with non-technical teammates or analysts.

ETL and data pipelines

Transform data between formats as one step in a data engineering workflow.

Feed BI and dashboard tools

Convert JSON to CSV so Tableau, Power BI or Looker can ingest it directly.

Common mistakes

CSV with no header row

Uncheck "Has Headers" if your CSV has no header line — otherwise the first data row is treated as column names.

Wrong delimiter from European Excel exports

Excel in many European locales exports CSV with semicolons instead of commas — auto-detect handles this case.

Expecting deep nesting to flatten fully

Only one level of nesting is flattened into columns — deeper structures are stored as a JSON string in the cell.

Why use this converter

It handles the real-world edge cases of CSV — mixed delimiters, quoted fields with embedded commas, and line breaks inside values — that many basic converters get wrong.

Everything runs client-side in your browser. No file is ever uploaded to a server, which matters when you're converting spreadsheets or API payloads with sensitive data.

Frequently asked questions

CSV is flat and tabular, organized as rows and columns separated by a delimiter. JSON is structured and hierarchical, built from key-value pairs and arrays that can nest inside each other. CSV is the natural fit for spreadsheets, while JSON is the standard format for APIs and web applications.

References

RFC 4180 — Common Format for CSV Files

The IETF specification defining the CSV format and its edge cases, such as quoting and line breaks.

JSON.org

The canonical reference for the JSON data interchange format.