Base64 Encoder Decoder - Encode & Decode Base64 Online

Base64 is a binary-to-text encoding scheme that represents binary data in an ASCII string format. It uses 64 printable characters (A-Z, a-z, 0-9, +, /) to encode binary data.

How Base64 Works:

• Encoding: Converts binary data (or text) into ASCII characters
• Safety: Ensures data can be safely transmitted over text-only protocols
• Size Increase: Encoded data is ~33% larger than original
• Reversible: Lossless encoding, original data can be fully recovered

Common Use Cases:

• JWT Tokens: Header and payload are Base64URL-encoded
• SAML Assertions: SAML responses are Base64-encoded XML
• Basic Authentication: Username:password encoded in HTTP headers
• Data URLs: Embedding images in HTML/CSS (data:image/png;base64,...)
• Email Attachments: MIME encoding for binary files in emails
• API Requests: Encoding binary data in JSON payloads

Base64 vs Base64URL:

• Base64: Uses + and / characters, may have = padding
• Base64URL: Uses - and _ (URL-safe), no padding. Used in JWTs

Client-side only: All Base64 encoding and decoding is performed locally in your browser using native JavaScript functions (btoa/atob). No data is sent to any server. Your content remains completely private.