Validate Base64 encoded strings instantly. Check format, padding, and encoding correctness.
Enter a Base64 string below to validate its format and structure
Base64 validation is the process of checking whether a string is correctly encoded in Base64 format. Valid Base64 strings must follow specific rules: they can only contain characters A-Z, a-z, 0-9, +, /, and padding character =, the length must be a multiple of 4, and padding must only appear at the end.
This validator checks all aspects of Base64 encoding including character validity, proper length, correct padding, data URI format detection, and provides detailed feedback about any issues found. It helps identify malformed Base64 strings before attempting to decode them.
Validate Base64 strings received from APIs before decoding
Check Base64 data integrity in databases or files
Verify Base64 encoding in unit tests and integration tests
Identify issues with Base64 encoded data in production
Yes, all validation happens entirely in your browser. Your Base64 data never leaves your device and is never sent to any server, ensuring complete privacy and security.
A valid Base64 string must: contain only A-Z, a-z, 0-9, +, / and = characters, have a length that's a multiple of 4, use padding (=) only at the end with at most 2 padding characters, and be decodable to valid data.
Yes! The validator automatically detects data URIs (starting with data:) and validates both the data URI format and the Base64 content within it.
Absolutely! This Base64 validator is completely free with no limitations, registration, or hidden costs.