Base64 Encoder & Decoder

What Base64 encoding actually does

Base64 converts binary or text data into a string built from only 64 safe characters, A through Z, a through z, 0 through 9, plus + and /, which makes it safe to embed inside places that only reliably handle plain text, like JSON fields, URLs, email attachments and data URIs. It is not encryption or compression, it is purely a format conversion, the encoded text is always exactly 33 percent longer than the original.

Where Base64 shows up in everyday web work

You will typically run into Base64 when inlining a small image directly into CSS or HTML as a data URI, when an API returns binary content like a file or image inside a JSON response, when decoding the payload of a JWT to inspect its claims, or when an email system encodes an attachment for transport.

Why UTF-8 text needs special handling

The browser's built-in btoa and atob functions were designed for Latin-1 text and will throw an error or produce garbled output on characters outside that range, like accented letters, currency symbols or non-Latin scripts. This tool wraps that process with UTF-8 aware encoding and decoding, so text with accents, emoji or non-English characters round-trips correctly.