Convert CSV to JSON or JSON to CSV — handles quoted commas, newlines in cells, custom delimiter — browser-only
- Runs locally
- Category Format Converter
- Best for Turning pasted content or local files into a handoff-friendly format.
What this tool does
Free online CSV ⇄ JSON converter. Paste CSV with a header row → get a JSON array of objects. Paste a JSON array → get CSV with auto-detected columns. Properly handles RFC 4180: quoted fields, escaped quotes ("" inside cells), and embedded newlines. Custom delimiter (comma, semicolon, tab, pipe). 100% client-side.
Tool details
- Input
- Text + Structured content
- The page exposes text boxes, numeric controls, file pickers, or structured inputs depending on the tool.
- Output
- Live result + Copy
- The result area focuses on usable output, with copy, download, or preview actions when supported.
- Privacy
- Browser-side processing
- The main tool logic does not call an external API, so inputs normally stay in the current tab.
- Save / share
- No account required
- Open the page and use it; whether results survive refresh depends on the tool.
- Performance budget
- Initial JS <= 10 KB
- No WASM budget is declared, keeping the tool quick to open on mobile.
- Best fit
- Format Converter · Developer
- Category and role tags drive related tools, internal links, and quick fit checks.
How to use
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1. Input
Paste or drop your content into the tool panel.
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2. Process
Click the button. All processing is local in your browser.
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3. Copy / Download
Copy the result or download to disk in one click.
How CSV ⇄ JSON Converter fits into your work
Use it when the main problem is getting content from one practical format into another.
Conversion jobs
- Turning pasted content or local files into a handoff-friendly format.
- Previewing a conversion before you use it in a larger workflow.
- Cleaning small format mismatches without opening a full editor.
Conversion checks
- Try a small sample first when the source format is messy.
- Check character encoding, separators, and line endings after conversion.
- Keep the source until the converted output has been reviewed.
Good next steps
These links move the current task into a more complete workflow.
- 1 YAML ⇄ JSON Converter Convert between YAML and JSON — both directions, pretty-printed, error messages with line numbers — browser-only Open
- 2 JSON Formatter & Validator Format, validate, and minify JSON instantly — right in your browser. Open
- 3 CSV to SQL Converter Turn CSV into CREATE TABLE + INSERT statements — type inference, safe value escaping, MySQL / PostgreSQL / SQLite — browser-only Open
Real-world use cases
Turn a 2,000-row Excel export into JSON for a seed script
You exported products.csv from Excel with 2,000 rows, and one column holds descriptions with commas and line breaks. Paste it, keep "First row is header" on, and copy the JSON array straight into your seed script. The quoted multi-line cells stay intact, so no row gets split in two the way a naive split-on-comma would do.
Reshape an API's JSON response into a CSV for a stakeholder
A teammate sends you 350 records as a JSON array but the finance lead only opens spreadsheets. Paste the JSON, switch to JSON→CSV, and the columns get auto-detected from the object keys. Open the result in Google Sheets in 10 seconds, no Python, no pandas, no "let me write a quick script" detour.
Clean up a semicolon-delimited export from German Excel
Your German colleague's export uses `;` as the separator because the comma is the decimal mark. Set the delimiter to semicolon and the parser reads it correctly, so 19,90 stays one field instead of becoming two. Convert to JSON, then back to comma-delimited CSV your US tools expect.
Sanity-check a headerless log dump before importing
A system dumped 500 lines with no header row. Toggle "First row is header" off so keys become col_1, col_2, col_3. Now you can eyeball the JSON, confirm column 3 is always a timestamp, and catch the 12 malformed rows before they break your import job downstream.
Common pitfalls
Splitting CSV on every comma yourself instead of parsing it — a cell like `"Smith, John"` becomes two columns. Let the parser respect the quotes.
Forgetting to turn off "First row is header" for headerless data, so your real first data row silently vanishes into keys. Check the first JSON object looks like data, not column names.
Assuming JSON→CSV preserves nested objects — a value like `{"city":"NYC"}` flattens to `[object Object]`. Flatten nested fields in the JSON before converting.
Privacy
Every conversion runs in your browser — the CSV and JSON you paste never leave the tab and are never sent to a server. Because spreadsheet exports can be large and may hold customer records or financials, the input is not written into the page URL, so nothing sensitive ends up in your history or a shared link. Close the tab and the data is gone.
FAQ
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