Base64 encode / decode

About this tool

Base64 turns binary data into ASCII text using 64 characters: A through Z, a through z, 0 through 9, plus + and /. It doesn’t encrypt anything, so anyone can decode it. What it does well is make arbitrary bytes safe to embed in places that only accept text, such as JSON payloads, data URIs, HTTP basic-auth headers, and email attachments. The exact rules for the alphabet and padding come from RFC 4648.

Paste text to encode it to Base64, or paste a Base64 string to decode it back. Everything runs locally in your browser. Nothing you type is uploaded to a server, which makes it safe to use with credentials, tokens, and other sensitive values.

People reach for this to read the credentials inside an Authorization: Basic header, inspect a data: URI, check what a Base64 blob in a config file or JWT segment actually contains, or encode a string for an API that requires Base64 input. For more on the encoding itself, see MDN’s Base64 glossary entry.