CyberChef
FreeGCHQ's open-source 'cyber Swiss army knife': chain hundreds of operations — base64, hex, compression, hashing, encryption, parsing — into recipes that transform data entirely client-side.
Why we recommend CyberChef
CyberChef, released as open source by the UK's GCHQ, replaces a folder of sketchy single-purpose converter sites with one composable tool: drag operations (From Base64 → Gunzip → JSON Beautify) into a recipe and watch data transform live. Everything runs client-side, which is precisely what you want when the data being decoded is sensitive. The 'Magic' operation even guesses the encoding chain for you.
Best use cases
Best for: security analysts unwrapping layered obfuscation in phishing payloads, developers debugging encoding issues (double-encoded URLs, mixed charsets, gzip-in-base64), CTF players, and anyone doing repeatable data cleanup who can save the recipe URL and rerun it later.
Honest limitations
The interface is dense and utilitarian — first-time users face a wall of 400+ operations. Very large files can freeze the tab since everything runs in browser memory. It is a transformation tool, not an analysis suite: no case management or reporting.
Are you the maker of CyberChef? Claim this listing →
More in Development Tools
Google's image compression tool — compare formats (WebP, AVIF, MozJPEG) side by side with live quality sliders. All processing is client-side, so images never leave your machine. A must-have for web developers.
Social front-end playground: write HTML, CSS and JavaScript in the browser with live preview, preprocessors and frameworks, then share pens and explore millions of community demos. Free accounts cover public work.
Cloud development environment for full projects: instant Node, React and framework templates, npm dependencies, live collaboration and shareable dev servers. Free tier covers public sandboxes and limited VM credits.
Instant dev environments that boot Node.js inside your browser tab via WebContainers — full npm installs and Vite dev servers with no remote VM. Free for public projects.
Browser IDE and hosting for dozens of languages with an AI agent that scaffolds and edits apps, real-time multiplayer editing, and one-click deployments. Free tier for trying and learning.
Regex sandbox with live matching, a full explanation tree for every token, a debugger that steps through backtracking, and quick reference for PCRE, JavaScript, Python and Go flavors.