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CSV to JSON Converter

Convert CSV to JSON array instantly online. Free CSV to JSON converter with header detection, type inference, and pretty-print output.

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CSV (Comma-Separated Values) is a plain-text tabular format with roots in 1970s mainframe data exchange, formally described in RFC 4180. It remains the lowest-common-denominator interchange format for spreadsheets and databases: virtually every data system can export to CSV, making it the universal starting point for data pipeline work.

Data engineers use CSV-to-JSON conversion constantly: transforming spreadsheet exports from Excel or Google Sheets into API-ingestible JSON arrays, loading CSV database exports into MongoDB or Elasticsearch, preprocessing datasets before feeding them to JavaScript-based data visualization libraries like D3.js or Vega, and migrating records between SaaS platforms.

This tool converts CSV to JSON using the papaparse library, a robust parser that handles RFC 4180-compliant CSV including quoted fields with embedded commas, escaped double-quotes, and multiline values. It automatically uses the first row as column headers to produce an array of named objects, with type inference for numbers and booleans.

Common Use Cases

Importing spreadsheet data into MongoDB

Business analysts export reports from Excel or Google Sheets as CSV files. Before inserting these records into MongoDB with mongoimport or a Node.js script using the official driver, the CSV must be converted to a JSON array. Each row becomes a document object with field names derived from the header row.

Feeding data to D3.js visualizations

D3.js and Observable Plot operate natively on JavaScript arrays of objects. When building charts from dataset exports — census data, financial CSVs from Bloomberg, scientific measurements — converting CSV to JSON first allows developers to manipulate and filter the data with standard Array methods before binding it to the visualization.

Preparing records for REST API ingestion

SaaS platforms like HubSpot, Salesforce, and Mailchimp expose bulk-import REST APIs that accept JSON arrays, not CSV. When migrating contact lists, product catalogs, or order histories exported from legacy systems, converting CSV to JSON is the required transformation step before POSTing records to the platform's batch import endpoint.

Converting database exports for Elasticsearch

PostgreSQL and MySQL exports via psql COPY or SELECT INTO OUTFILE produce CSV files. Bulk-indexing these records into Elasticsearch using the _bulk API requires newline-delimited JSON (NDJSON). Converting CSV to a JSON array is the first step before flattening each object into an action/source pair for the bulk indexer.

How to Use the CSV to JSON Converter

  1. Paste or type your CSV data in the left panel.
  2. The first row is automatically used as header keys.
  3. JSON array output appears automatically as you type.
  4. Click "Copy Output" to copy the JSON to your clipboard.
  5. Use "Load Example" to see a sample CSV dataset.

CSV Format Tips