JSON vs Parquet: Which Format Should You Choose?

JSON is flexible and Parquet is compact. The right choice depends on who reads the file.

The short answer. Use JSON for data that apps and APIs send back and forth, and for small files people may read. Use Parquet for large tables that you store and analyze.

Size. The same 100,000-row table is 14.76 MB as compact JSON and 1.84 MB as Parquet, about 8 times smaller. Even after gzip, JSON is 1.63 MB and Parquet 1.35 MB. Parquet stores each column together and compresses it, while JSON repeats every field name in every row.

Speed and types. Tools such as DuckDB, Spark, BigQuery and pandas can read just the columns they need from a Parquet file, and they know each column type. A JSON file must be read and parsed in full. Parquet is not readable in a text editor, though, and nested data needs care when you convert it.

Converting. In Data Utility you can convert JSON to Parquet and back in your browser. In our test, 100,000 rows took about 0.4 seconds, and the file is never uploaded. Check the row count and the column types after any conversion.

Open the JSON to Parquet converter

Related tool pages

  • JSON, CSV, Parquet and Excel Converter: Convert between JSON, CSV, Parquet and Excel online for free, one file or a whole folder. It runs in your browser, so nothing is uploaded.
  • JSON to CSV Converter: Convert JSON to CSV online for free. Drop a file or paste data, click convert and download. It runs in your browser, so your data is never uploaded.
  • CSV to JSON Converter: Convert CSV to JSON online for free. Drop a file or paste data, click convert and download. It runs in your browser, so your data is never uploaded.
  • CSV to Parquet Converter: Convert CSV to Parquet online for free. Drop a file or paste data, click convert and download. It runs in your browser, so your data is never uploaded.
  • Parquet to CSV Converter: Convert Parquet to CSV online for free. Drop a file or paste data, click convert and download. It runs in your browser, so your data is never uploaded.
  • Parquet to JSON Converter: Convert Parquet to JSON online for free. Drop a file or paste data, click convert and download. It runs in your browser, so your data is never uploaded.

How to use the JSON to Parquet converter: step by step

  1. Open the JSON to Parquet converter.
  2. Drop in your JSON file.
  3. Convert and download.
  4. Open the result to check rows and types.

When to use the JSON to Parquet converter

  • Pick a format for stored data
  • Cut the size of a JSON data export
  • Explain why analysts prefer Parquet
  • Open a Parquet file as JSON

Example

Input: [{"id":1,"name":"Ada","age":36},{"id":2,"name":"Alan","age":41}]

Output: A Parquet file with the same columns (id, name, age) and typed values.

Frequently asked questions

How do I convert JSON to Parquet?

Drop your JSON file (or paste the data), check the options, click Convert and download the Parquet result.

How big can a file be?

It depends on your device. A few hundred MB usually works.

Which conversions does the Format Converter support?

Any direction between JSON, CSV, Parquet and Excel (.xlsx), for one file or a whole folder. Nested JSON is flattened into columns such as address.city. For Excel, the first sheet is read; old .xls files are not supported.

Why did my number or date change after converting?

Types are detected from the values. Turn off "Detect types" to keep everything as text, which also keeps leading zeros in IDs and phone numbers.

Tip: Nested JSON becomes columns such as address.city. Check the column names before you load the file into a database.