About This Tool

A private-first file toolkit built for everyday work.

Data Transformer is a free, browser-based utility for cleaning, converting, and exporting spreadsheets and text. No account. No uploads. No surprises.

How it works

Three steps — all local, all instant.

1

Drop or paste your data

Upload a CSV, Excel file, or paste any plain text directly in the browser. No file size limits imposed by servers.

2

Transform in-browser

Deduplicate rows, clean formatting, or convert plain text to structured Markdown — entirely inside JavaScript, on your device.

3

Export the result

Download your cleaned file as CSV, JSON, Excel (.xlsx), or Markdown (.txt). The file is generated locally and saved directly to your device.

Privacy is not a feature — it's the foundation.

Every computation happens inside your browser tab. Your files never touch our servers because we don't have any. The moment you close the tab, your data is gone. We designed it this way deliberately — the fewer systems your data passes through, the safer it stays.

What you can do with it

Remove duplicate rows

Identify and strip exact-match duplicate rows from any CSV or Excel file in one click.

Convert between formats

Export any spreadsheet as a clean CSV, JSON array, or formatted Excel file without reformatting by hand.

Convert plain text to Markdown

Paste unstructured prose or prompts — the tool detects headings, lists, and key-value pairs and outputs clean Markdown.

Preview before you export

Inspect a live data preview or Markdown source before downloading — no guesswork about what the output looks like.

Built with open-source libraries

No proprietary dependencies, no vendor lock-in.

PP

PapaParse 5.4

CSV parsing

XS

SheetJS 0.18

Excel reading & writing

TW

Tailwind CSS

Styling

VN

Vanilla JS

No framework

Ready to get started?

No sign-up. No install. Just open the tool and drop your file.

Open the tool