Base64 Encoding Explained: What It Is & When to Use It

What is Base64 Encoding?

Base64 is a binary-to-text encoding scheme that represents binary data in an ASCII string format. It uses 64 characters (A-Z, a-z, 0-9, +, /) to encode data, making it safe for transmission over text-based protocols like email, HTTP, and JSON.

How Base64 Works

Base64 takes 3 bytes of binary data and converts them into 4 ASCII characters. Each Base64 character represents 6 bits of the original data. The "=" character is used for padding when the original data isn't perfectly divisible by 3.

Common Use Cases

• Email attachments (MIME): Binary files are Base64 encoded for email
• Data URLs: Embedding images in HTML/CSS (e.g., data:image/png;base64,...)
• API authentication: Basic auth sends username:password in Base64
• JSON data: Sending binary data in JSON payloads
• URL shortening: Some URL shorteners use modified Base64

Base64 is NOT Encryption

Base64 is encoding, not encryption. Anyone can easily decode Base64 back to its original form. Never use Base64 for security purposes — it provides no confidentiality.