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CSV ↔ JSON Converter

Turn spreadsheet exports into JSON for APIs, or flatten JSON arrays into CSV you can open in Excel. Runs entirely in your browser.

Paste CSV to convert to JSON
Delimiter
Auto picks comma, semicolon, or tab from the first rows.

Input

Output

Conversion runs entirely in your browser. CSV and JSON never upload to Tokitool.

How to use

How to convert CSV to JSON (or JSON to CSV)

Pick a direction, paste or upload your file, convert, then copy or download. Nothing leaves your device.

  1. Choose a direction. Use CSV JSON for spreadsheet exports headed to an API, or JSON CSV when you want rows in Excel or Sheets.
  2. Paste or upload. Drop CSV/TSV/JSON into the input, or use Upload file. For CSV, leave Delimiter on Auto unless you know the separator.
  3. Convert. Click Convert. Errors for empty input, bad JSON, or unreadable CSV show above the panels, not only in the console.
  4. Copy or download. Copy the result, or download .json / .csv for the next tool in your workflow.

CSV to JSON and JSON to CSV in the browser

Spreadsheets speak CSV. APIs and config often speak JSON. Tokitool’s CSV ↔ JSON Converter sits between those two worlds without sending your rows to a third-party upload site. That matters when the file has customer emails, invoice lines, or internal IDs you should not paste into a random “convert online” box.

When CSV → JSON helps

Export a sheet from Excel, Google Sheets, or a CRM as CSV, then convert here so the first row becomes object keys and each following row becomes an object in a JSON array. That shape is what most REST endpoints and scripts expect. Auto-detect covers comma (US/UK exports), semicolon (many EU locales), and tab (TSV).

When JSON → CSV helps

Paste an array of objects from an API response or a log dump. Headers come from the union of object keys. Nested objects and arrays are flattened with dotted keys (for exampleaddress.city) so the sheet stays one cell per value. Pure nested trees that are not a list of records will not convert; wrap them as an array of objects first.

What this tool is not

  • Not a full database or ETL suite. Multi-megabyte dumps may slow the tab; split large files.
  • Not a schema validator. It converts structure; it does not check business rules.
  • Not a cloud sync. Close the tab when you are done on a shared computer.

Need to pretty-print the JSON after converting? Open the JSON Formatter. For Base64-wrapped payloads, use the Base64 Encoder / Decoder first. Privacy model: private browser tools.

CSV ↔ JSON FAQ

Is my CSV or JSON uploaded anywhere?

No. Parsing and conversion run in your browser only. Tokitool does not receive the file contents.

Does the first row become JSON keys?

Yes for CSV JSON. The first row is treated as headers. Duplicate header names get a numeric suffix so keys stay unique.

What happens to nested JSON objects?

On JSON CSV, nested objects and arrays are flattened with dotted paths (address.city) or indexed keys for arrays. That keeps one row per top-level object.

Which CSV delimiters are supported?

Comma, semicolon, and tab. Auto mode scores the first rows and picks the most likely separator. Override with the Delimiter buttons if Auto guesses wrong.

Does this work with large files?

Everyday exports (thousands of rows) are fine in a modern browser. Very large files can freeze the tab because everything stays in memory. Split the file or use a local script for multi‑MB dumps.

Can I convert a single JSON object?

JSON CSV expects an array of objects. A single object is accepted and treated as one row. A bare array of primitives is not enough; use objects with named fields.