Base64 Encoding: What It Is and How to Use It

Base64 is a binary-to-text encoding scheme that converts binary data into a string of ASCII characters. It is widely used in web development, email systems, and data storage.

How Base64 Works

Base64 takes every 3 bytes (24 bits) of binary data and converts them into 4 ASCII characters. It uses 64 characters: A-Z, a-z, 0-9, +, and /. The = character is used for padding when the input is not evenly divisible by 3.

Common Use Cases

Embedding Images in HTML/CSS

Small images can be embedded directly in HTML or CSS using Base64 data URIs, eliminating the need for separate HTTP requests.

Email Attachments

MIME (email) protocol uses Base64 to encode binary attachments so they can be transmitted as text through email servers.

API Data Transfer

APIs often use Base64 to encode binary data (like files or images) within JSON payloads, since JSON only supports text.

Storing Binary Data

Databases that only support text fields can store binary data as Base64-encoded strings.

Important Notes

Base64 is NOT encryption. It is an encoding scheme that anyone can decode. Never use Base64 to protect sensitive data. Also, Base64 increases data size by approximately 33%, so it is best used for small pieces of data.