What is a Base64 validator?
A Base64 validator checks whether a string is decodable and reports common issues such as invalid characters, bad padding, mixed alphabets, and data URL wrappers.
How to use it
- Paste the Base64 string.
- Read the status, decoded size, alphabet, and padding details.
- Repair or normalize the string if errors appear.
Example
Input: SGVsbG8sIFdvcmxkIQ==
Output: status Valid Base64
Common mistakes
- A string can be valid Base64 but still decode to binary rather than text.
- Missing padding may be acceptable in Base64URL but not in every decoder.
- Mixed standard and URL-safe characters are a warning sign.
Related tools
- Fix common issues with Repair malformed Base64.
- Clean format with Base64 normalize.
- Decode valid text with Base64 to text.
Privacy and security
Validation runs locally in your browser.