Use Free Data Tools Offline: Install Data Utility as an App

Convert, clean and query data with no internet connection, and no file ever leaving your computer.

Open the Format Converter

Data Utility is a browser app: your files are processed on your own device. That also means it can work offline. Install it from the sidebar (or the browser install icon) and it opens in its own window.

Use Make available offline in the sidebar once, while you are online. It stores the larger engines, DuckDB for SQL on files and the OCR engine for screenshot to CSV, so every tool works without a network. The DuckDB and English OCR engines are served from the site itself, not from a third-party CDN.

This helps on corporate VPNs, in air-gapped labs, on planes, and when you simply want proof that nothing is sent anywhere: switch off Wi-Fi and the tools keep working.

Open the Format Converter

Related tool pages

  • Avro Viewer Online: Open .avro Files: Open and view an Avro (.avro) file online: see the schema and records as a table, then save as CSV, JSON, Excel or Parquet. Free, no upload.
  • Avro to CSV Converter: Convert an Avro file to CSV online. Nested records are flattened. Free, private, runs in your browser.
  • CSV to Avro Converter: Convert CSV to an Avro (.avro) file online. Column types are detected and written into the Avro schema. Free and private: nothing is uploaded.
  • Avro to JSON Converter: Convert an Avro file to JSON online. Nested records, arrays and maps stay nested. Free, private, no upload.
  • JSON to Avro Converter: Convert JSON to an Avro (.avro) file online. The schema is built from your data. Free, private, no upload.
  • Avro to Parquet Converter: Convert Avro to Parquet online for faster analytics in Spark, DuckDB or BigQuery. Free, private, runs in your browser.

Also try

How to use the Format Converter: step by step

  1. Open Data Utility and choose Install desktop app.
  2. Click Make available offline and wait for it to finish.
  3. Disconnect from the internet.
  4. Open the app and use any tool as usual.

When to use the Format Converter

  • Working with sensitive data on a restricted network
  • Converting files on a plane or train
  • Running SQL on a CSV with no connection
  • Demonstrating to security teams that data stays local

Example

Input: id,name,age 1,Ada,36 2,Alan,41

Output: [{"id":1,"name":"Ada","age":36},{"id":2,"name":"Alan","age":41}]

Frequently asked questions

How big can a file be?

It depends on your device. A few hundred MB usually works.

Which conversions does the Format Converter support?

Any direction between JSON, CSV, Parquet and Excel (.xlsx), for one file or a whole folder. Nested JSON is flattened into columns such as address.city. For Excel, the first sheet is read; old .xls files are not supported.

Why did my number or date change after converting?

Types are detected from the values. Turn off "Detect types" to keep everything as text, which also keeps leading zeros in IDs and phone numbers.

Tip: Other OCR languages download once from the default host the first time you use them, so use them once online.