Turning a one-off Google Sheets / Excel export into seed data for an API mock or test fixture. Loading reference tables (countries, currency codes, lookup data) into a frontend that consumes JSON. Inspecting a CSV with embedded commas / newlines that gets misrendered everywhere except a real RFC 4180 parser.

Delimiter detection isn't magic. If your file uses semicolons (common in EU locales) or tabs (TSV), switch the delimiter dropdown — auto-detection guesses but can be fooled by data containing the wrong character. Type coercion is opinionated. Numeric strings, true , false , and literal null are converted to JSON types. Things that look numeric but aren't (zip codes, ISBNs with leading zeros, phone numbers) lose leading zeros — disable coercion or post-process. Empty cells become empty strings, not null . Most APIs treat the two differently. BOMs in the wild. Excel often saves UTF-8 with a byte-order mark on Windows; the parser tolerates it but other consumers may not.

CSV to JSON

Convert CSV data to JSON arrays. Header detection, custom delimiters, quoted fields, and embedded newlines handled.

Delimiter

Has header row?

CSV input

JSON output

Enter input above to see the result.

What is this for?

CSV is the lingua franca of spreadsheet exports; JSON is the lingua franca of APIs and config. This converter takes properly-quoted CSV (RFC 4180-compatible) and emits a JSON array — either an array of objects (when there's a header row) or an array of arrays. Useful when you've exported a sheet and need to feed it into something that talks JSON.

When to use it

Turning a one-off Google Sheets / Excel export into seed data for an API mock or test fixture.
Loading reference tables (countries, currency codes, lookup data) into a frontend that consumes JSON.
Inspecting a CSV with embedded commas / newlines that gets misrendered everywhere except a real RFC 4180 parser.

Common gotchas

Delimiter detection isn't magic. If your file uses semicolons (common in EU locales) or tabs (TSV), switch the delimiter dropdown — auto-detection guesses but can be fooled by data containing the wrong character.
Type coercion is opinionated. Numeric strings, true, false, and literal null are converted to JSON types. Things that look numeric but aren't (zip codes, ISBNs with leading zeros, phone numbers) lose leading zeros — disable coercion or post-process.
Empty cells become empty strings, not null. Most APIs treat the two differently.
BOMs in the wild. Excel often saves UTF-8 with a byte-order mark on Windows; the parser tolerates it but other consumers may not.