Free Web Tools That Respect Your Privacy

Your privacy is our priority. We process all data locally in your browser, ensuring nothing leaves your device.

Text and Code

JSON

Validate JSON and transform it into TypeScript interfaces automatically.

Diff Checker

Compare text versions and easily identify changes.

Regex

Test, break down, and get human-readable explanations for your Regular Expressions.

Converters and Encoders

Spreadsheet

Convert spreadsheets (XLS, XLSX, CSV, ODS) to JSON and vice versa with high precision and ease.

Base64

Reliable Base64 encoding and decoding for your data.

URI

Encode and decode URIs for secure web transmissions.

Colors and Images

Colors

Choose colors and see their values in different formats.

SVG Tools

Convert SVG to PNG, ICO, WebP, or React components.

Image Tools

Convert images to different formats and sizes.

DEV Utilities

Cron

Easily create and validate cron expressions for your schedules.

UUID & Passwords

Generate random UUIDs and secure passwords instantly.

HAR Viewer

Inspect .har files visually — requests, status codes, timings, and headers at a glance.

Organization and Focus

To Do

Organize your tasks and boost your productivity with our synchronized list.

Timer

A precise timer to help you manage your focus blocks.

Bookmarks

Save your useful links and access them from anywhere with ease.

Essential Tools for Developers

Data ManipulationConvert spreadsheets and JSON with high type fidelity.

Encoding & DebuggingBase64, URI and more — works 100% offline.

Assets & FrontendSVG to PNG, ICO, WebP, or React component instantly.

Privacy First

dnnr.dev does not send your data to any server. All processing happens locally in your browser. Secrets, passwords, and client data never leave your machine.

No Server Processing

No Tracking

Open Source Spirit

Except purposeful storage tools (To-Do, Bookmarks).

Frequently Asked Questions

Quick answers to the most common questions about tools.dnnr.dev. Our goal is to make using the tools simple and straightforward, so we've gathered everything you need to know here. If you still have questions, you can freely explore the tools or contact us to learn more.