Convert NDJSON to Parquet Online
Convert NDJSON files to Parquet format directly in your browser. No upload required — your data never leaves your device.
About this conversion
This tool converts NDJSON files to Parquet format directly in your browser — no account required, no file upload, no waiting for a server. It processes your data entirely within your browser using WebAssembly, so nothing ever leaves your device.
The tool preserves all columns and data types from your source file and writes a valid Parquet file ready to download. Large files are handled efficiently using a vectorised columnar engine.
Not sure which format you need? Read our NDJSON vs CSV comparison for a side-by-side breakdown.
Frequently Asked Questions
What is Parquet format?
Parquet is an open-source columnar storage format designed for efficient analytics. It compresses far better than CSV and is natively supported by Spark, Athena, BigQuery, Pandas, and DuckDB.
Is my NDJSON data private?
Yes — completely. Your file is never uploaded to any server. All conversion happens inside your browser using WebAssembly — locally, with no upload. Once you close the tab, nothing is retained.
What is the maximum file size?
The free limit is 50 MB. For larger files, performance depends on your device's available memory — most modern machines can handle 500 MB to 1 GB comfortably.
What is the difference between NDJSON and Parquet?
Both NDJSON and Parquet are common data formats used in engineering and analytics workflows.
Related Tools
Coalesce Columns in Parquet Files Online
Fill null values in Parquet files from other columns — return the first non-null value across up to 8 columns in priority order. Add the result as a new column. Runs entirely in your browser.
Add UUID Column to Parquet Files Online
Add a UUID column to Parquet files directly in your browser. Generate random UUIDv4 or time-ordered UUIDv7 identifiers for every row. Choose the column name and position — no upload required.
Pad Column in Parquet Files Online
Left-pad or right-pad a column in Parquet files to a fixed width directly in your browser. Zero-pad numeric codes, pad product IDs to a fixed length, or right-pad text fields — no upload required.
Compute Percentiles for Parquet Files Online
Compute percentiles, median, MAD, mode, and kurtosis for numeric columns in Parquet files directly in your browser. Optionally group by a category column. Results download as CSV — no upload required.
Find Arg Max / Min in Parquet Files Online
Find the value of one column at the row where another column is maximum or minimum in Parquet files — directly in your browser. Optionally group by a category to get per-group results. No upload required.