JSON to Parquet Converter
Handle Million Rows in Your Browser

Convert JSON files to Apache Parquet format instantly in your browser. Paste JSON text directly or upload a .json file. Powered by DuckDB-WASM with Snappy compression, no server upload required.

Drag & drop your file here, or browse

Accepts: .json (up to 500 MB)

Your data stays in your browser. By using this tool, you agree to our Terms and Privacy Policy.

How to Convert JSON to Parquet

Choose the "Upload File" tab and drag & drop your .json file, or switch to the "Paste Text" tab and paste your JSON data directly.

The tool reads your JSON using DuckDB-WASM. Supported formats: Array of objects ([{...}, {...}]) and NDJSON (one object per line).

Preview the output schema and data.

Click the download button to save the Parquet file.

Features

100% Browser-Based: Your data never leaves your device. All conversion happens locally using WebAssembly — no server upload, no privacy concerns.
3–10x Smaller Output: Apache Parquet uses columnar storage and Snappy compression. The Parquet file is typically 3–10x smaller than the equivalent CSV representation of the same data.
Paste or Upload: Paste JSON directly into the text area or upload a .json file. Perfect for quick tests or batch conversions.

JSON vs Parquet: What's the Difference?

JSON (JavaScript Object Notation) is a lightweight text-based format widely used for APIs and application data exchange. Apache Parquet is a columnar binary format optimized for analytics, with built-in compression and strict type preservation.

	JSON	Parquet
Storage	Text (key-value pairs)	Columnar binary
File size	Larger (key names repeated)	3-10x smaller (compressed)
Data types	Strings, numbers, booleans, null	Integer, Float, Date, Boolean (strict)
Read speed	Must parse entire file	Column pruning + predicate pushdown
Common use	Web APIs, config files, NoSQL	Data lakes, Spark, BigQuery, DuckDB

Benefits of Converting JSON to Parquet

Drastically reduce file size with columnar storage and compression
Preserve data types (integers, dates, booleans) — no more string parsing
Enable faster queries in analytics tools like DuckDB, Spark, and BigQuery

Frequently Asked Questions

Is my data uploaded to a server?

No. Your file never leaves your browser. All processing happens locally using WebAssembly. No data is sent to any server.

Is it free?

Yes, this tool is completely free with no row limits.

What JSON structures are supported?

This tool supports JSON arrays of objects (e.g., [{"id": 1}, {"id": 2}]) and NDJSON (newline-delimited JSON). Each object becomes a row, and keys become column headers. Wrapper objects like {"data": [...]} are not supported — extract the inner array first.

Can I convert a large JSON file with millions of rows to Parquet?

Yes. This tool uses DuckDB-WASM to process files entirely in your browser. It handles millions of rows and the Parquet output is typically much smaller than the original JSON due to columnar storage and compression.

Can I paste JSON directly instead of uploading a file?

Yes. Switch to the "Paste Text" tab and paste your JSON data directly. The tool validates and converts it instantly. For pasted text, the limit is 10MB — use file upload for larger data.

What compression is used?

The output uses Snappy compression by default, which offers a good balance of compression ratio and speed. Snappy is widely supported by Spark, BigQuery, DuckDB, and other analytics tools.

What is the file size limit?

The input limit is 500MB for file upload. For pasted text, the limit is 10MB. The Parquet output is typically much smaller than the JSON input due to columnar storage and compression.

I got an error during conversion

Parquet requires strict column types. If the same key contains mixed types in your JSON (e.g., "age": 25 in some rows and "age": "unknown" in others), the type inference may fail. Ensure each key uses a consistent data type across all objects.

Can I clean up or filter data before converting?

This page is a dedicated conversion tool. For data cleansing before conversion, try LeapRows — no sign-up required.

What browsers are supported?

Any modern browser with WebAssembly support: Chrome, Firefox, Edge, Safari (14+).