Base64 Encoder Decoder Online — Free URL and JWT Tool
Encode or decode Base64 and URL strings instantly in your browser. Also decodes JWT tokens to show header, payload and claims. Free, no signup, nothing uploaded.
About Base64 encoding
Base64 converts binary data (like images or files) into a text-safe string of 64 characters. It is widely used in email attachments, data URIs, and API authentication headers like Authorization: Basic ....
About URL encoding
URL encoding replaces unsafe characters (spaces, symbols, non-ASCII) with percent codes like %20 for space. Required when passing data in query strings or path segments so the URL remains valid.
About JWT decoding
A JSON Web Token has three Base64URL-encoded parts separated by dots: header.payload.signature. This tool decodes the header and payload so you can inspect claims like sub, exp, and iat.
Important: decoding is not the same as verifying. This tool does not check whether the token is signed correctly or whether it can be trusted.