Base64 Encoder/Decoder — Developer Code Samples

Base64 encoding converts binary data to ASCII text using a 64-character alphabet. Use Python's base64 module, JavaScript's btoa/atob functions, or the base64 CLI tool for fast encoding and decoding without any external libraries.

Try the interactive version online: Open Base64 Encode/Decode Tool →

Parameters

Parameter	Type	Required	Description
text	str	Yes	Input text or binary data to encode
url_safe	bool	No	Use URL-safe alphabet (- and _ instead of + and /)
encoding	str	No	Character encoding for text input (default: utf-8)

Returns: Base64-encoded ASCII string, or decoded original text/bytes

Code Examples

import base64

# Encode text to Base64
text = "Hello, World!"
encoded = base64.b64encode(text.encode('utf-8')).decode('ascii')
print(encoded)
# Output: SGVsbG8sIFdvcmxkIQ==

# Decode Base64 back to text
decoded = base64.b64decode(encoded).decode('utf-8')
print(decoded)
# Output: Hello, World!

# URL-safe Base64 (no + or / characters)
url_safe = base64.urlsafe_b64encode(b"binary data here").decode('ascii')
print(url_safe)

# Encode a file to Base64
def encode_file(filepath):
    with open(filepath, 'rb') as f:
        return base64.b64encode(f.read()).decode('ascii')

# Decode Base64 and write to file
def decode_to_file(b64_string, output_path):
    data = base64.b64decode(b64_string)
    with open(output_path, 'wb') as f:
        f.write(data)

// Encode text to Base64 (browser)
const text = "Hello, World!";
const encoded = btoa(text);
console.log(encoded);
// Output: SGVsbG8sIFdvcmxkIQ==

// Decode Base64 (browser)
const decoded = atob(encoded);
console.log(decoded);
// Output: Hello, World!

// Handle Unicode strings (browser)
function encodeUnicode(str) {
  return btoa(encodeURIComponent(str).replace(/%([0-9A-F]{2})/g,
    (match, p1) => String.fromCharCode(parseInt(p1, 16))
  ));
}

function decodeUnicode(str) {
  return decodeURIComponent(atob(str).split('').map(c =>
    '%' + ('00' + c.charCodeAt(0).toString(16)).slice(-2)
  ).join(''));
}

// Node.js Buffer approach
const buf = Buffer.from("Hello, World!", "utf-8");
const nodeEncoded = buf.toString("base64");
const nodeDecoded = Buffer.from(nodeEncoded, "base64").toString("utf-8");

# Encode text
echo -n "Hello, World!" | base64
# Output: SGVsbG8sIFdvcmxkIQ==

# Decode Base64
echo "SGVsbG8sIFdvcmxkIQ==" | base64 --decode

# Encode a file
base64 image.png > image.b64

# Decode to file
base64 --decode image.b64 > restored.png

# URL-safe Base64 (replace + with - and / with _)
echo -n "hello" | base64 | tr '+/' '-_' | tr -d '='

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