About

DecodeThis is a free, open developer toolbox that auto-detects what you paste and instantly parses, decodes, formats, and converts it — all within your browser.

Why DecodeThis Exists

Developers accumulate a lot of bookmarked tools: a token decoder, a JSON formatter, a Base64 decoder, a URL parser, a YAML validator, and so on. Every time you need to inspect some data, there's a small mental tax — figuring out which tool to open, navigating to it, and pasting your data in the right place.

DecodeThis replaces all of that with a single tool. Paste anything, and it figures out what you're looking at. It auto-detects the format, decodes any encoding layers, and shows you the parsed result. The goal is to reduce friction to nearly zero: paste and see.

Privacy First

Every bit of processing happens in your browser. No data is sent to any server, ever. This means you can safely paste production tokens, API keys in configuration files, certificates, and other sensitive data without worrying about it being logged or intercepted. You can verify this yourself in your browser's Network tab — the only network requests are for loading the application itself.

How It Works

When you paste data, DecodeThis runs a fast detection pass using pattern matching to identify the format. It then loads the appropriate parser and renders a specialized view for that format: tree views for structured data, decoded headers for tokens, color swatches for color values, human-readable timestamps, and more.

Encoded data is automatically unwrapped. A Base64 string containing JSON is decoded and then formatted. A SAML assertion inside a URL parameter is extracted and inflated. The tool follows the chain of encodings to get you to the actual data with minimal effort.

Creator

DecodeThis is created and maintained by Nick Stallman.