Free developer tools that run entirely in your browser.
decode64.com is a collection of free online tools for developers, designers, and anyone who works with data formats. Every tool runs 100% in your browser — no data is sent to any server, no account required, no tracking.
The site started as a Base64 decoder and has grown into a full developer toolkit covering encoding, formatting, conversion, generation, and hashing utilities.
When you paste sensitive data into any tool on this site — a JWT token, a private key encoded in Base64, a confidential JSON payload — it stays on your device. We don't run analytics, we don't log inputs, and we don't have a backend that touches your data.
This is not a marketing claim. It is a technical fact: all processing happens in JavaScript in your browser tab. You can verify this by disconnecting from the internet after the page loads — the tools keep working.
decode64.com currently offers tools for Base64 encoding and decoding, JWT token inspection, JSON formatting and minification, URL encoding, HTML entity conversion, color picking, QR code generation, UUID generation, CSV/JSON conversion, HTML and YAML formatting, CSS minification, epoch timestamp conversion, hash generation, and SQL formatting.
New tools are added regularly. See the full tools list.
The site is built with plain HTML, CSS, and vanilla JavaScript. No frameworks, no build pipeline, no Node.js. Pages are hosted on Cloudflare Pages and served from a global CDN, so load times are fast regardless of your location.
All tools work offline once the page is loaded. External CDN scripts are only used for specific tasks where a well-tested library is safer than a custom implementation (e.g., CryptoJS for hash functions).
For questions, bug reports, or tool suggestions, use the contact form at decode64.com/contact or email [email protected].