CSV · JSON · Parquet · SQL
Free Online Data Tools for CSV, JSON & Parquet
Analyze, query, clean and convert your data directly in your browser.
Browser-based tools process your files locally whenever possible.
SELECT country, COUNT(*)
FROM data
GROUP BY country
ORDER BY COUNT(*) DESC;Your CSV is exposed as a table, so ordinary SQL works against it.
Why DataToolsOnline
Browser-based processing
Tools are built on DuckDB-Wasm, so the work happens on your device instead of on a server.
No signup
There are no accounts. Open a tool and use it.
Privacy-first by design
Core tools do not upload your files to our servers or send your data to analytics.
Free tools
The core browser tools for viewing, profiling, querying and converting are free.
Data tools by format
Data engineering tools that run in your browser, grouped by what you are working with.
CSV Tools
View, profile, clean and convert CSV files locally.
- CSV ViewerOpen large CSV files in a fast, searchable, sortable table.
- CSV ProfilerColumn-by-column statistics computed from your actual data.
- CSV CleanerTrim, deduplicate, rename and filter, then export a cleaned CSV.
- CSV to ParquetComing soonConvert CSV to compressed, typed, columnar Parquet.
- CSV to JSONComing soonConvert CSV rows to a JSON array or newline-delimited JSON.
- CSV to SQLComing soonGenerate CREATE TABLE and INSERT statements from a CSV file.
Parquet Tools
Open, inspect and convert Parquet files without uploading them.
- Parquet ViewerInspect the schema, rows and real file structure of a Parquet file without uploading it.
- Parquet ProfilerColumn statistics and real file structure for Parquet files, computed locally.
- Parquet to CSVComing soonConvert a Parquet file to CSV locally.
- Parquet to JSONComing soonConvert a Parquet file to JSON or newline-delimited JSON.
JSON Tools
Format, explore, flatten and convert JSON.
- JSON ViewerValidate, search and explore any JSON document as a virtualized tree.
- JSON FormatterPretty-print or minify JSON with clear, position-aware validation errors.
- JSON FlattenerFlatten nested JSON into flat key paths, previewed before export.
- JSON to CSVConvert JSON arrays to CSV, flattening nested fields.
- JSON to ParquetConvert JSON records to typed Parquet, with nested structure preserved.
SQL Tools
Run SQL directly against CSV and Parquet files with DuckDB.
Data Quality
Find potential problems in a dataset and get suggested fixes.
Want to understand a concept first?
Short, concrete explanations of CSV, Parquet, JSON and data-quality concepts, each pointing to the tool that puts them into practice.
- What Is Data Profiling?What profiling actually computes, and how it differs from a data-quality check.
- CSV vs Parquet: Which Should You Use?How the two formats actually differ, with real size and speed numbers, not vibes.
- What Is Data Quality?A concrete definition: the specific, checkable problems it covers and why language matters.
How it works
- 01
Choose your file
Drag in a CSV, JSON or Parquet file, or pick one from disk.
- 02
Process it in your browser
DuckDB-Wasm reads the file locally. Large files get a size warning first.
- 03
Analyze or transform your data
Profile columns, check quality, run SQL, clean or convert.
- 04
Download your result
Export the output as CSV, JSON or Parquet.