Base64 Encoder

What is Base64 Encoding?

Base64 is a binary-to-text encoding scheme that represents binary data in an ASCII string format. It's commonly used to encode binary data for transmission over media that only support text, such as email or HTTP. Developed as part of the MIME (Multipurpose Internet Mail Extensions) standard, Base64 has become a fundamental encoding mechanism in modern web development, APIs, and data exchange protocols.

Common Uses of Base64 Encoding

• Data URIs in HTML/CSS: Embedding images and other files directly in HTML or CSS using data URIs (e.g., data:image/png;base64,iVBORw0KG...). This eliminates separate HTTP requests for small images, improving page load times. Commonly used for icons, small logos, and inline SVGs.
• JSON API Transmission: Sending binary data through JSON APIs that only support text. Since JSON is a text format, you cannot directly include binary data (images, PDFs, encrypted data). Base64 encoding converts binary to text, allowing transmission in JSON payloads. RESTful APIs frequently use this for file uploads and downloads.
• Email Attachments (MIME): MIME (Multipurpose Internet Mail Extensions) uses Base64 to encode email attachments. When you send a PDF, image, or any file via email, it's typically Base64 encoded in the MIME message body. The receiving email client decodes it back to the original file.
• HTTP Basic Authentication: HTTP Basic Authentication uses Base64 to encode credentials (username:password) in the Authorization header. For example, "Authorization: Basic dXNlcjpwYXNzd29yZA==" where the encoded string is "user:password" in Base64. Note: This is NOT secure without HTTPS, as Base64 is easily decoded.

Is Base64 Encoding Secure?

Base64 is encoding, not encryption. It provides no security and can be easily decoded by anyone. Never use Base64 alone to protect sensitive data. Learn about encoding security

Base64 Encoding in Programming Languages

Most programming languages have built-in functions for Base64 encoding. Here are examples in popular languages:

// Basic encoding
$encoded = base64_encode($data);

// Encoding UTF-8 string
$text = "Hello, 世界!";
$encoded = base64_encode($text);

// Encoding file contents
$fileData = file_get_contents('image.png');
$encoded = base64_encode($fileData);

// Browser (btoa for ASCII only)
const encoded = btoa('Hello'); // Basic ASCII

// Browser with UTF-8 support
const encoded = btoa(unescape(encodeURIComponent('Hello, 世界!')));

// Modern browsers with TextEncoder
const encoder = new TextEncoder();
const data = encoder.encode('Hello, 世界!');
const encoded = btoa(String.fromCharCode(...data));

import base64

# Encode string (automatic UTF-8)
text = "Hello, 世界!"
encoded = base64.b64encode(text.encode('utf-8')).decode('ascii')

# Encode bytes directly
data = b'\x00\x01\x02\x03'
encoded = base64.b64encode(data).decode('ascii')

# Encode file
with open('image.png', 'rb') as f:
    encoded = base64.b64encode(f.read()).decode('ascii')

import "encoding/base64"

// Basic encoding
data := []byte("Hello, 世界!")
encoded := base64.StdEncoding.EncodeToString(data)

// URL-safe encoding
encoded := base64.URLEncoding.EncodeToString(data)

// Encoding to writer (for large data)
encoder := base64.NewEncoder(base64.StdEncoding, outputWriter)
encoder.Write(data)
encoder.Close()

import java.util.Base64;
import java.nio.charset.StandardCharsets;

// Basic encoding
String text = "Hello, 世界!";
String encoded = Base64.getEncoder()
    .encodeToString(text.getBytes(StandardCharsets.UTF_8));

// URL-safe encoding
String encoded = Base64.getUrlEncoder()
    .encodeToString(text.getBytes(StandardCharsets.UTF_8));

// MIME encoding (line breaks every 76 chars)
String encoded = Base64.getMimeEncoder()
    .encodeToString(text.getBytes(StandardCharsets.UTF_8));

require 'base64'

# Basic encoding
text = "Hello, 世界!"
encoded = Base64.encode64(text)

# Strict encoding (no newlines)
encoded = Base64.strict_encode64(text)

# URL-safe encoding
encoded = Base64.urlsafe_encode64(text)

using System;
using System.Text;

// Basic encoding
string text = "Hello, 世界!";
byte[] bytes = Encoding.UTF8.GetBytes(text);
string encoded = Convert.ToBase64String(bytes);

// With line breaks (for MIME)
string encoded = Convert.ToBase64String(bytes,
    Base64FormattingOptions.InsertLineBreaks);

Related Tools

Need to decode Base64? Use our Base64 Decoder to convert Base64 strings back to original text or binary data.

Working with URLs? Try our URL Encoder to make text URL-safe.

Displaying content on web pages? Use our HTML Entity Encoder to prevent XSS attacks.