CSV to JSON Converter
Convert CSV files to JSON format. Supports custom delimiters and headers.
Transform CSV data into JSON format with support for custom delimiters (comma, semicolon, tab, pipe) and optional headers. Perfect for data migration and API integration.
CSV is how spreadsheets and legacy systems export data; JSON is how modern APIs expect to receive it. Converting between the two sounds trivial until you hit the edge cases: commas inside quoted fields, embedded newlines, fields that are themselves quoted, a header row that may or may not exist, and inconsistent column counts across rows. A real conversion has to handle RFC 4180 properly, not just split on commas.
This converter parses CSV according to RFC 4180 and produces one of two JSON shapes. The default is an array of objects where keys come from the header row — [{"name": "Ada", "role": "engineer"}, ...] — which is what every REST API expects. The alternative is an array of arrays, useful when there's no header or when column order matters more than key names. Delimiters can be commas, semicolons (common in European locales where comma is the decimal separator), tabs (TSV), or pipes.
Type inference is optional. With it on, the string "42" becomes a number, "true" becomes a boolean, and empty cells become null. With it off, every value stays as a string — safer when downstream code expects exact fidelity, like preserving leading zeros in ZIP codes or phone numbers.
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Paste CSV or upload a file
Drop CSV text or upload a .csv file. The parser detects the delimiter automatically but you can override it if auto-detection guesses wrong.
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Configure the output shape
Choose whether the first row is a header (produces array of objects) or not (produces array of arrays). Toggle type inference for numbers, booleans, and nulls.
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Copy or download the JSON
Copy the formatted JSON to clipboard or download as a .json file. The output is ready to POST to an API or drop into a database seed script.
Importing spreadsheets into APIs
Export a Google Sheet as CSV, convert to JSON, and POST it to your API — no intermediate scripting required.
Database seed data
Convert a CSV of sample customers or products into JSON for use as a seed file in Prisma, Sequelize, or a plain fixture.
Feeding test data to a mock server
Mock APIs like json-server expect JSON. Convert a stakeholder's spreadsheet into the right shape in one step.
Migrating from legacy exports
Old systems often export CSV. Convert to JSON so modern tools (Elasticsearch, MongoDB, Algolia) can ingest it directly.
Does it handle quoted fields with commas inside?
Yes. The parser follows RFC 4180: fields enclosed in double quotes can contain commas, newlines, and escaped quotes (doubled ""). Unquoted fields are split only on the configured delimiter.
What if my CSV uses semicolons or tabs instead of commas?
Pick the delimiter from the dropdown — commas, semicolons, tabs, or pipes are all supported. Semicolons are common in German, French, and other locales where comma is the decimal separator.
How does type inference work?
With inference on, "42" becomes 42, "true" and "false" become booleans, and empty cells become null. Leave it off to keep every value as a string — useful for IDs, ZIP codes, and phone numbers where leading zeros matter.
Can it handle files with no header row?
Yes. Switch the header toggle off and the output becomes an array of arrays, preserving column order. Add your own keys afterward if needed.
Are there size limits?
Files up to about 50 MB convert comfortably in the browser. For multi-gigabyte exports, use a streaming tool like csvkit, miller, or DuckDB's read_csv.