Easy File Tools

Easy File Tools

Free online developer tools

These utilities are grouped by the development question they answer: how content renders, how payloads can be reduced or encoded, and what a browser or network input actually reports.

Free to useNo account required

Choose a tool

Open the tool for the task you want to complete. Each page explains its inputs, processing behavior, and output.

Preview and edit

Render Markdown or HTML while you work.

Markdown previewer

Edit Markdown with a live preview panel.

HTML editor

Edit HTML with a live preview panel.

Minify and generate

Reduce source text or create test identifiers and barcodes.

Code minifier

Minify and beautify CSS, HTML, and JavaScript.

Barcode generator

Create printable Code 128, EAN-13, and UPC-style barcode images.

Credit card generator

Generate valid test credit card numbers for development.

Diagnose network and input

Inspect DNS answers or confirm keyboard events.

DNS lookup

Check DNS records across public resolvers with a dig-style answer view.

Keyboard tester

Test keyboard keys and detect stuck keys.

Questions about developer tools

Does code minification change how a program behaves?

A correct minifier preserves behavior, but aggressive transformations can expose assumptions in fragile code. Keep source control and test the minified artifact in its target environment.

Why can DNS results differ between resolvers?

Caching, geographic routing, resolver policy, DNSSEC validation, and propagation timing can produce different answers or TTLs for the same name.

Are generated card numbers real payment credentials?

No. They are checksum-valid test values only and do not include a funded account, authorization, or security code tied to a financial institution.