About FastKit

What FastKit is

FastKit is a collection of free online utilities for everyday technical tasks: text and encoding tools, color and image tools, date and time tools, cryptography and developer tools, and API testing. There are no accounts, no paywalls and no downloads — you open a page and the tool is ready.

The site is built around one core principle: your data stays on your device. Almost every tool here — from the scratchpad and image editor to the hash and encryption utilities — runs entirely inside your browser using JavaScript and the Web Crypto API. The text you paste, the images you compress and the keys you generate are processed locally and are never uploaded to our servers.

Why we built it

Most online tool sites are cluttered with sign-up walls, "upload your file to our cloud" flows, and tools that quietly send your input to a backend. We wanted the opposite: fast, focused utilities that respect privacy by design. Because the processing happens in your browser, these tools also work when your connection is slow — and a few of them keep working even after you go offline completely.

They are aimed at developers, designers, students and anyone who occasionally needs to decode a JWT, convert a timestamp, resize a screenshot or generate a batch of UUIDs without installing anything.

How it works

FastKit is a statically pre-rendered website served over HTTPS. Cryptographic operations use either well-audited open-source libraries (such as @noble/ciphers) or the browser’s native Web Crypto API. Image tools run on the HTML canvas and in Web Workers. History and drafts that need to survive refreshes are stored in your browser’s localStorage and IndexedDB, which you can wipe at any time from the tool itself or from your browser settings.

The site is available in ten languages: English, 简体中文, Español, Deutsch, Français, Português, 日本語, 한국어, Русский and हिन्दी. Every page, including this one, is fully translated, and your browser remembers which language you used last.

Who maintains it

FastKit is maintained by an independent developer who builds privacy-first web utilities. The site is free to use; advertising helps cover hosting. If you have feedback, found a bug, or want to suggest a tool, the contact page has the way to reach us — we read everything.