Dev Toolbox

Everyday developer tools in one popup: format JSON, decode JWT, convert cURL and more. Runs fully local, nothing is uploaded.

Dev Toolbox puts the small developer tasks you would normally open several websites for into one browser popup. Paste something in and the detector works out what it is and opens the matching tool. You can format and validate JSON and query it with JSONPath, read the contents of a JWT without sending it anywhere, turn a cURL command into JavaScript request code, and create QR codes with an optional logo. A header profile switcher adds custom request headers to the sites you choose, which is handy when testing different environments. It also includes an encoder and decoder for common text formats, a generator for IDs and strong passwords, a URL parameter editor, text statistics and a timestamp converter. The QR tool can also read codes: paste or drop a screenshot and it decodes the code right in your browser, then lets you open the result in the matching tool. Select text on any page and right-click to open it in the matching tool. Everything runs locally in your browser. There is no account, no server, no tracking and no network requests. What you type into a tool is kept only in browser memory and is cleared when you close the browser. Quick access: press Alt+Shift+D on any page to check your clipboard, or type dt and a space in the address bar to convert a timestamp.