Base64 Decoder
About the Base64 Decoder
A Base64 Decoder is an essential utility that helps you transform a Base64 ASCII string back into its original, readable text. It reverses the encoding process used to safely embed binary or text data inside systems that only handle plain text, such as emails, URLs, and JSON payloads.
Base64 decoding maps each group of four Base64 characters back to the three original bytes they represent, stripping any trailing = padding along the way. This is especially useful for reading encoded API responses, inspecting JWT token payloads, revealing the content behind a data:...;base64,... URI, or checking what's actually inside an HTTP Basic Authentication header.
How to Use the Base64 Decoder
Paste the Base64 string
Enter the Base64 encoded text into the input box.
Click "Decode"
The tool converts it back to its original, readable text.
Copy the result
Use the "Copy" button to use the decoded text anywhere you need.
Common Use Cases
Reading Encoded API Payloads: Inspect the real content of a Base64 field returned by an API response.
Debugging JWT Tokens: Decode the header and payload segments of a JSON Web Token to inspect its claims.
Extracting Data URIs: Reveal the original content behind a data:...;base64,... string.
Decoding Basic Auth Headers: Reveal the username and password encoded in an HTTP Authorization header.
Verifying Encoded Config Values: Check that a Base64-encoded environment variable or config value decodes to what you expect.
Why Use This Base64 Decoder
Instant Decoding
Get results immediately, right in your browser, without any delay.
Handles Unicode & Emoji
Decodes the underlying UTF-8 bytes, so multibyte characters come back correctly.
Clear Error Messages
Flags invalid or malformed Base64 input instead of silently failing.
Private & Secure
All decoding happens locally in your browser — your data is never stored or shared.
Free & Online
No downloads needed — access it from any browser, anywhere.
One-Click Copy
Copy the decoded output straight to your clipboard.