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Data Profiler

Open Data Profiler

Drop a CSV, JSON, or Parquet file and get instant statistics — all in your browser.

What it shows

  • Summary: row count, column count, file size, duplicate row count
  • Per-column profile:
    • Data type (VARCHAR, INTEGER, DOUBLE, etc.)
    • Null count and percentage (with visual bar)
    • Distinct value count
    • Min / Max values
    • Mean, Median, Std Dev (for numeric columns)
    • Top 10 most frequent values

Supported formats

Format Extensions Max Size
CSV .csv ~500 MB
JSON .json, .jsonl, .ndjson ~500 MB
TSV .tsv ~500 MB
Parquet .parquet, .pq ~500 MB

How it works

  1. File is read into browser memory as an ArrayBuffer
  2. DuckDB-WASM registers the file and auto-detects format
  3. SQL queries compute statistics for each column
  4. Results render as interactive cards

No data is uploaded. Everything runs in your browser tab.

Source code

github.com/freedatastore-online/data-profiler