CSV to JSON Converter

Convert CSV to JSON in your browser — header row becomes keys, each row an object.

100% Browser-Based • Local Processing

World-class parsing engine with real-time colorful syntax visualization.

Messy CSV Input

0 bytes

Colorful JSON Output

0 records
🧩 RELATED TOOLS
JSON to CSV JSON Formatter JSON Validator All Developer Tools

Privacy Focused

🔒 Local Processing. Your code never leaves your device.

Instant Results

🌐 Fully Client-Side. Runs instantly in your browser.

No Signup

⚡ No accounts. No API keys. Just open and use.

Browser Based

🚀 No installs, no CLI, no build step.

Overview

Convert CSV to JSON — privately

CSV to JSON converts tabular CSV data into JSON. The header row becomes the keys, and each following row becomes a JSON object — so the output is an array of objects. This one runs entirely in your browser, so your CSV is never uploaded, and it handles quoted fields correctly.

CSV is how spreadsheets and databases export tabular data, but most code and APIs want JSON. This converter bridges the two: it reads your CSV and turns the header row into keys and each data row into an object, producing a clean array of objects ready to drop into your app.

Paste your CSV or load a local file, set the delimiter (comma, semicolon, tab, or a custom character), choose whether the first row is a header, and optionally enable type inference to convert numbers and booleans (otherwise everything stays a string). The parser follows RFC 4180, so it correctly handles quoted fields that contain commas, quotes (escaped as ""), or even embedded newlines. Output can be pretty-printed or minified, and you can copy or download it, along with a row/column count.

Privacy is the point. Everything runs in your browser — no server, no upload, no logging, no tracking. CSVs frequently hold real data: customer exports, financial records, spreadsheets. Here, none of it leaves your device, and the tool works offline once loaded.

Two honest notes worth knowing. First, CSV is only loosely standardised — delimiters, quoting, encodings, and line endings vary between tools — so while this converter follows RFC 4180 and lets you pick the delimiter, unusually formatted CSV may need a tweak. Second, type inference is a heuristic: turning it on can silently misread values like ZIP codes, phone numbers, or IDs with leading zeros (01234 becoming 1234) as numbers. When identifiers matter, keep values as strings.

For the reverse, see JSON to CSV; to tidy the output, the JSON Formatter.

Use cases

When CSV to JSON helps

  • Feeding APIs. Turn a spreadsheet export into JSON for a request or import.
  • Seeding data. Convert sample CSV into JSON fixtures.
  • Config from spreadsheets. Let non-devs edit CSV, ship JSON.
  • Quick inspection. See tabular data as structured objects.
  • Sensitive exports. Convert real data files without uploading them.
Guide

How to convert CSV to JSON

Paste or load your CSV

Type it, paste it, or open a local file (read in-browser, not uploaded).

Set the delimiter and header

Comma, semicolon, tab, or custom; mark whether row 1 is a header.

Choose type handling

Keep everything as strings, or infer numbers and booleans.

Convert

The tool produces an array of objects (or arrays), pretty or minified.

Copy or download

Grab the JSON. Nothing is sent anywhere.

Realistic example

name,age\nAda,36\nGrace,45 becomes [{"name":"Ada","age":"36"},{"name":"Grace","age":"45"}] — or with type inference, the ages become numbers.

Advanced tip

If your data has IDs or codes with leading zeros, leave type inference off so 007 stays "007" instead of 7.

Common mistake to avoid

If the output looks like one giant column, your delimiter is wrong — switch it to semicolon or tab to match your file.

Related

To go back, use JSON to CSV.

Good to know

What to keep in mind

  • Zero-knowledge and private. Parsing runs in your browser — nothing uploaded, logged, or tracked, and it works offline.
  • CSV is loosely standardised. Delimiters, quoting, encodings, and line endings vary; set the delimiter to match your file.
  • Type inference is heuristic. It can turn 01234 into 1234 — keep values as strings when leading zeros or IDs matter.
  • RFC 4180 quoting supported. Quoted fields with commas, escaped quotes, and newlines are handled.
  • Large files run locally. Very big CSVs are limited by your device, since there's no server.
Support

Frequently Asked Questions

How do I convert CSV to JSON?

Paste your CSV (or load a local file), set the delimiter and whether the first row is a header, and the tool turns the header row into keys and each data row into a JSON object — producing an array of objects. Optionally infer numbers and booleans. Then copy or download the JSON. Everything happens in your browser; nothing is uploaded.

Does this upload my CSV, and does it work offline?

No upload, and yes it works offline. All parsing happens in your browser using JavaScript — there's no server receiving your data, no logging, and no tracking. That matters because CSVs often hold real data like customer exports or financial records. Once the page has loaded it keeps working with no internet connection, which you can confirm in your browser's network tab.

What does the JSON output look like?

By default it's an array of objects: the header row supplies the keys, and each data row becomes one object with those keys mapped to its values. For example, columns name,age produce [{"name":"Ada","age":"36"}, ...]. You can also choose an array of arrays if you'd rather keep the raw row structure without keys. Output can be pretty-printed or minified.

My CSV uses semicolons or tabs — can it handle that?

Yes. Set the delimiter to semicolon, tab, or a custom character to match your file. Many European spreadsheets export semicolon-separated values (because the comma is a decimal separator), and tab-separated (TSV) is common too. If your converted output looks like a single column, the delimiter is almost certainly wrong — switch it to the one your file actually uses.

Does it handle quoted fields with commas or newlines?

Yes. The parser follows RFC 4180, so fields wrapped in double quotes can safely contain commas, line breaks, and escaped quotes (written as two double quotes, ""). This means a value like "Smith, Ada" is treated as one field, not split at the comma. Proper quote handling is what separates a real CSV parser from a naive split-on-comma.

How do I keep leading zeros (ZIP codes, IDs)?

Turn type inference off so all values stay strings. Type inference converts things that look like numbers into numbers, which strips leading zeros — turning a ZIP like 01234 into 1234, or an ID 007 into 7. That's usually not what you want for identifiers. Keeping values as strings preserves them exactly; only enable inference when you genuinely want numeric/boolean types.

Can I convert numbers and booleans instead of strings?

Yes. Enable type inference and the tool converts values that look like numbers (36 → 36) and booleans (true/false) into their JSON types, and can map empty values to null. This is handy when the JSON feeds code that expects real numbers. Just be careful with identifiers and leading zeros, where you'll want inference off to keep them as strings.

What if my CSV has no header row?

Turn the "first row is header" option off. Then the tool won't treat row one as keys — instead it can output an array of arrays (each row as a list of values), or generate generic keys like column1, column2. Use this when your data is purely positional or when the header is missing, and add your own keys afterward if needed.

Can I get an array of arrays instead of objects?

Yes. Choose the array-of-arrays output shape and each CSV row becomes a JSON array of its cell values, preserving the raw tabular structure without keys. This is useful when column order matters more than names, when there's no header, or when you're feeding something that expects rows-and-columns rather than named fields. The default, though, is the more common array of objects.

Can I load a CSV file instead of pasting?

Yes. You can open a local .csv file and the tool reads it directly in your browser with the FileReader API — the contents load into the editor without being uploaded anywhere. This is ideal for larger exports or ones you'd rather not copy and paste, and it's exactly as private as pasting the data by hand.

Can it handle large CSV files?

Usually yes. Because it runs locally, the limit is your device's memory and CPU rather than a server cap, and modern browsers handle files with tens of thousands of rows well. Very large files (hundreds of MB) can be slow or hit memory limits, since everything is processed in-browser — but nothing is uploaded, and there's no server-imposed size cap.

Is it free, and are there limits?

Yes, completely free — no payment, no signup, no account, and no usage caps or watermarks. Since everything runs in your browser, there's nothing for us to meter; the only practical limit is your device's performance on very large files. Use it as much as you like, including offline once the page has loaded.

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