Base64 Decoder

About this tool

The Base64 decoder is the complementary tool to the encoder, allowing you to reverse the encoding process to recover the original data. This tool is essential when working with APIs, authentication systems, or any system that transmits binary data encoded as text. The decoding process takes the Base64 string, validates its format, and converts it back to its original binary representation, which can be text, images, PDFs, or any other data type. It's especially useful for decoding JWT tokens, extracting embedded images from data URIs, or recovering binary data stored in text-based databases. The tool processes everything locally in your browser using the native atob() API, ensuring that sensitive data is never sent to external servers. It's important to note that Base64 is not encryption, so anyone with access to the encoded string can easily decode it.

Use cases

• Decode JWT tokens to inspect their content
• Extract embedded images from HTML/CSS data URIs
• Decode HTTP Basic authentication credentials
• Recover binary data stored in databases as text

Frequently asked questions

What's the difference between encoding and decoding Base64?

Encoding converts binary data to Base64 text. Decoding does the reverse, converting Base64 text back to the original binary data.

Is it safe to decode sensitive data in the browser?

This tool processes everything locally in your browser, so data is not sent to external servers. However, remember that Base64 is not encryption, it doesn't protect information.

What happens if I try to decode an invalid Base64 string?

If the string is not valid Base64, the tool will show an error indicating the problem. Invalid strings may have incorrect characters or incorrect length.

Can I decode Base64 that contains special characters like + or /?

Yes, the decoder supports all standard Base64 characters (A-Z, a-z, 0-9, +, /, =). The + and / characters are part of the standard Base64 alphabet.