Base64 Encoder/Decoder

What is Base64 Encoding?

Base64 is a group of binary-to-text encoding schemes that represent binary data (like images, files, or executable code) in an ASCII string format. It is called "Base64" because it uses a set of 64 characters to represent data: A-Z, a-z, 0-9, +, and /. It also uses = for padding at the end of the string.

Computers store data in binary (0s and 1s). However, many older protocols (like email via SMTP) were designed to handle only plain text. If you try to send a raw image or a binary file through these systems, the data can get corrupted because some binary patterns might be interpreted as control characters. Base64 solves this by translating that binary data into a safe, printable text format.

Common Uses for Base64

1. Data URIs (Images in HTML/CSS)

Web developers often use Base64 to embed small images (like icons or logos) directly into HTML or CSS files instead of referencing an external image file. This reduces the number of HTTP requests the browser has to make, potentially speeding up page load times.

Example: <img src="data:image/png;base64,iVBORw0KGgo..." />

2. Email Attachments (MIME)

When you send an email with a PDF or JPEG attachment, your email client automatically encodes that file into a Base64 string. The receiving email server decodes it back into the original file for the recipient to view.

3. Basic Authentication

In HTTP Basic Authentication, the username and password are joined by a colon (user:password) and then encoded in Base64 before being sent in the HTTP header.

Base64 vs. Encryption: A Critical Distinction

It is a common misconception that Base64 is a way to "hide" or "encrypt" data. Base64 is NOT encryption.

• Encoding (Base64): Transforms data into a new format so it can be safely transmitted. It requires no key and can be decoded by anyone.
• Encryption (AES, RSA): Scrambles data to keep it secret. It requires a private key or password to decrypt.

Never use Base64 to store sensitive data like passwords or credit card numbers unless it is also encrypted.

Frequently Asked Questions