What is mini-tools.dev?

mini-tools.dev is a clean, fast, and completely free collection of developer utilities built for people who write code every day. Whether you need to format a messy JSON payload, decode a Base64 string, generate a SHA-256 checksum, or quickly understand a cron expression, everything you need is here — no sign-up, no waiting, no nonsense.

Every single tool on this site runs entirely in your browser. When you paste a JSON blob into the formatter, or type a password into the generator, that data is processed locally using JavaScript running on your own device. Nothing is sent to a server. Nothing is logged. Nothing is stored anywhere except, optionally, your browser's localStorage for remembering your dark mode preference.

Why we built it

Developers spend a surprising amount of time on tiny tasks that have nothing to do with their actual work. Need to convert an epoch timestamp? You end up on some ad-plastered website that loads three analytics scripts, asks you to disable your ad-blocker, and then pastes your data through a server somewhere just to do basic arithmetic.

We got tired of it. There is no good reason a tool that formats JSON or decodes a URL needs to be slow, privacy-invasive, or cluttered with distractions. These are simple browser-side operations. They should be instant, clean, and private by default. mini-tools.dev is the alternative we wanted — so we built it.

Our principles

• Privacy by default. Your data never leaves your device. All processing happens client-side using standard browser APIs and well-audited JavaScript libraries. We do not log inputs, outputs, or any identifying information.
• Zero accounts required. You should not need to create an account to format a JSON string. No sign-up, no email, no password, ever.
• Offline-capable. Most tools work even without a network connection once the page has loaded. The logic lives in the browser, not on a remote server.
• Open and free. Every tool is completely free to use, forever. No premium tiers, no rate limits, no paywalled features.
• Fast and focused. No heavy frameworks loaded on top of frameworks. Pages load quickly and get out of your way so you can get back to work.

The tools

mini-tools.dev currently offers eleven tools:

• Epoch Converter — Convert Unix timestamps to human-readable dates and back again, instantly.
• JSON Formatter — Format, validate, and minify JSON with error detection and syntax highlighting.
• YAML ↔ JSON Converter — Seamlessly convert between YAML and JSON, useful for config files and API payloads.
• URL Encoder/Decoder — Percent-encode and decode URLs and query parameters.
• HTML Entity Encoder — Convert special characters to and from HTML entities to prevent rendering issues and XSS.
• QR Code Generator — Generate customizable QR codes and WhatsApp direct-link QR codes for any URL or text.
• QR Code Reader — Decode any QR code from an uploaded image or your device's live camera, entirely in the browser.
• Hash Generator — Generate MD5, SHA-1, SHA-256, SHA-384, or SHA-512 hashes from any text input.
• Base64 Encoder/Decoder — Encode and decode text and images to and from Base64, including data URI generation.
• Password Generator — Create cryptographically secure, highly customizable passwords and passphrases using the Web Crypto API.
• Cron Job Descriptor — Translate complex cron expressions into plain English so you know exactly when a job will run.

Who built it

mini-tools.dev was built and is maintained by a solo developer who reaches for these utilities on an almost-daily basis. The frustration of repeatedly landing on slow, ad-heavy tool sites led to building this collection as a personal project — and then making it public so anyone else who feels the same way can use it too.

If you have a suggestion for a new tool, found a bug, or just want to say hello, head over to the contact page. Feedback is always welcome and new tools are added regularly.