Base64 Decoder

Decode Base64 strings with our Base64 Decoder tool. Features dual functionality to both encode and decode Base64 in one convenient interface. Perfect for API development, JWT token inspection, data URL creation, and debugging Base64-encoded data. Includes switch mode for easy conversion between encoding and decoding. Ideal for developers working with Basic Authentication, JSON/XML APIs, email attachments, and embedded resources. All processing happens in your browser for maximum privacy and security.

About Base64 Encoder/Decoder Tool

What is Base64?

Base64 is an encoding scheme that converts binary data into ASCII text format using 64 printable characters (A-Z, a-z, 0-9, +, /). It's commonly used to encode data that needs to be stored or transferred over media designed to handle text, such as JSON, XML, or email.

Why Use Our Base64 Encoder/Decoder Tool?

  • Dual Functionality: Both encode and decode in one tool.
  • Instant Conversion: Real-time encoding and decoding.
  • Switch Mode: Easily flip between encoding and decoding.
  • Copy & Clear: One-click copy and clear functions.
  • Free & Secure: All processing happens in your browser.

Common Use Cases

  • API Development: Encode credentials for Basic Authentication.
  • Data URLs: Embed images directly in HTML/CSS.
  • JSON/XML: Include binary data in text-based formats.
  • Email Attachments: MIME encoding for email attachments.
  • JWT Tokens: Decode JSON Web Token payloads.
  • URL Parameters: Safely pass binary data in URLs.

Frequently Asked Questions (FAQ)

What is Base64 encoding used for?

Base64 encoding is used to represent binary data in ASCII text format. This is useful when you need to transmit or store binary data over systems that only support text, such as email, JSON APIs, or XML files.

Is Base64 encryption?

No, Base64 is NOT encryption. It's simply an encoding scheme that can be easily reversed. Anyone can decode Base64 text. Never use Base64 alone for sensitive data - it provides no security.

Why does Base64 increase file size?

Base64 encoding increases data size by approximately 33% because it uses only 64 characters to represent 256 possible byte values. Three bytes of binary data become four Base64 characters.

Can I encode images to Base64?

Yes! Base64 is commonly used to encode images for data URLs. However, this tool is designed for text. For images, you'll need to read the file as binary data first, then encode it.

What does the padding '=' mean in Base64?

The '=' character is used for padding when the input length isn't divisible by 3. It ensures the Base64 output is always a multiple of 4 characters. One or two '=' characters may appear at the end.

Tips for Using Base64

  • Not for Security: Base64 is encoding, not encryption. Don't use it to hide sensitive data.
  • API Authentication: Basic Auth uses Base64 encoding for credentials.
  • Data URLs: Use Base64 to embed small images directly in HTML/CSS.
  • JWT Decoding: Decode JWT tokens to inspect their contents (but verify signatures!).
  • Size Consideration: Remember Base64 increases data size by ~33%.
  • Character Set: Base64 uses A-Z, a-z, 0-9, +, / and = for padding.

Base64 Variants

  • Standard Base64: Uses +, / and = (this tool)
  • Base64URL: Uses -, _ instead of +, / (URL-safe)
  • Base64 without padding: Omits the = padding characters

When to Use Base64

  • Text-Only Systems: When transmitting binary data over text-only protocols.
  • JSON/XML: Including binary data in structured text formats.
  • Email: MIME encoding for email attachments.
  • Data URLs: Embedding resources directly in web pages.
  • API Tokens: Representing binary tokens as text.

When NOT to Use Base64

  • Security: Base64 is not encryption. Use proper encryption algorithms.
  • Large Files: The 33% size increase can be significant for large files.
  • Binary Storage: If the system supports binary, use it directly.
  • Password Storage: Never "encrypt" passwords with Base64. Use proper hashing.

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