Base64 Encoder & Decoder

What is Base64 Encoding?

Base64 encoding is an algorithm that translates arbitrary binary or text data into a safe, printable ASCII format using a specific alphabet (A-Z, a-z, 0-9, +, and /). This encoding scheme ensures that complex payloads are transmitted reliably across systems that natively handle text. If you need to convert pictures rather than text, use our Base64 image converter instead.

Originally designed for older protocols like SMTP, Base64 is ubiquitous in modern web development. Whether you are generating an Authorization header, passing complex state in a URL string, or serializing data for a database, you will encounter Base64.

Unlike many online utilities, our Base64 Encoder strictly operates client-side. When dealing with authentication credentials, API tokens, or proprietary JSON configurations, privacy is critical. Because this tool leverages native JavaScript btoa() and atob() APIs directly in your browser, your sensitive strings are never transmitted over the internet or logged in a remote server.

When Should I Use This?

Base64 is not encryption—it is a transport mechanism. You should reach for Base64 encoding when:

• HTTP Basic Authentication: Web servers expect credentials formatted as username:password encoded in Base64 within the Authorization: Basic <token> header.
• Data URIs in CSS/HTML: Small inline graphics or fonts can be converted to Base64 and embedded directly to save network requests.
• Encoding Binary Data in JSON: JSON cannot natively store binary data (like uploaded files). Converting it to Base64 allows it to sit safely inside a JSON payload string.
• Debugging JWTs: JSON Web Tokens are composed of three Base64url-encoded parts. Decoding the header or payload fragments helps verify token claims.

// Encoding (Ensure UTF-8 support for emojis/special chars)
const encoded = btoa(unescape(encodeURIComponent("Hello World 🌍")));

// Decoding
const decoded = decodeURIComponent(escape(atob(encoded)));

# Encode text
echo -n "user:password" | base64

# Decode text
echo "dXNlcjpwYXNzd29yZA==" | base64 --decode

Troubleshooting Common Issues

• Malformed or corrupted text after decoding: Standard Base64 functions fail on Unicode characters. If you decode a string and see random garbled text (like é), it means the original encoder didn't correctly convert the string to UTF-8 bytes first. Our tool handles UTF-8 automatically to prevent this.
• "Invalid character" errors: If you try to decode a string and receive an error, check if the string contains URL-encoded characters (like %3D instead of =) or if it is actually Base64url encoded (contains - and _ instead of + and /).