Base64 Encoder & Decoder

Base64 is a binary-to-text encoding (RFC 4648) used for transporting binary data through text-only systems like email attachments, JWT payloads, and HTTP headers. This tool encodes UTF-8 text to Base64 or decodes a Base64 string back to its original bytes — entirely in your browser via the native btoa/atob and TextEncoder APIs. Nothing is sent to a server.

URL-safe Base64 (used in JWTs and OAuth state parameters) swaps +// for -/_ — the decoder handles either variant automatically.