Parquet Viewer
Open Parquet files online and browse the data with pagination. Inspect the schema, view rows page by page and export to CSV or JSON - processed entirely in your browser.
What is a Parquet file?
Apache Parquet is a columnar storage format widely used in big data tools such as Spark, Hive and Pandas. It stores data column by column with efficient compression, which makes analytical queries very fast.
How do I open a Parquet file online?
Drag your .parquet file into the upload area. The file is parsed in a Web Worker with the hyparquet library: the row count and column schema appear first, then you can browse the data 100 rows at a time.
Is my Parquet file uploaded to a server?
No. The file is read entirely inside your browser. Every page of rows is decoded on your device, so confidential datasets never leave your computer.
How do I convert Parquet to CSV or JSON?
Use the Export CSV or Export JSON buttons. The tool reads the file in chunks, shows a progress bar while assembling the output, and downloads a .csv or .json file with all rows.
Is there a limit on export size?
Files with more than 1,000,000 rows cannot be exported, to keep the browser from running out of memory. Browsing the data with pagination still works for files of any size.
Which compression codecs are supported?
SNAPPY, GZIP, BROTLI, ZSTD, LZ4 and LZ4_RAW are supported through the bundled hyparquet-compressors module. If a file uses an unsupported codec, the schema stays visible and an error explains what failed.
Can I see the column names and types?
Yes. The schema panel lists every column with its physical Parquet type, taken from the file metadata. Nested fields are shown with their full dotted path.
Why do I only see 100 rows at a time?
Large files are read page by page to keep the browser responsive. Use the Prev and Next buttons to move through the pages; the label shows the current page and total pages.
What do NULL and binary values look like?
Missing values are shown as NULL. Binary columns are displayed with their size in bytes; in the JSON export they become a readable size placeholder and in CSV only the byte count is written.
Is this a real Parquet parser?
Yes. The tool uses hyparquet, an open-source Apache Parquet implementation in pure JavaScript, running inside a Web Worker so large files do not freeze the page.
How to Use Parquet Viewer
Parquet is a compact columnar format that spreadsheets can't open. Drop a .parquet file here to inspect its schema and browse the rows page by page, then export what you need as CSV or JSON — all parsing happens locally.
- Click the drop zone or drag a .parquet file onto it. The file name, size and total row × column counts appear at the top of the panel.
- Check the Schema table first — it lists every column with its Parquet type, so you know what each field holds before scrolling through the data.
- Browse the Data table 100 rows at a time with the Prev and Next buttons; the label between them shows which page you are on. NULL cells and binary values are labelled as such.
- Press Export CSV for a spreadsheet-ready file, or Export JSON for structured data — a progress bar tracks the conversion row by row.
- Files with more than one million rows can be viewed but not exported; filter them at the source if you only need a subset.
DECIMAL and TIMESTAMP columns become plain text in the CSV — when importing it into a spreadsheet, set those columns' types manually so precision and dates survive the round trip.
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