Base64 Converter
Instantly encode or decode Base64 strings. 100% client-side with full unicode support and complete privacy.
Developer guide
About Base64 Converter
What is Base64 encoding?
Base64 represents binary bytes as printable text using a 64-character alphabet. It is commonly used for email attachments, data URLs, basic authorization examples, and JWT segments. Base64 is an encoding, not encryption: anyone with the value can decode it. Base64URL changes two characters and commonly removes padding so values can travel safely in URLs and token fields.
How to decode Base64 safely
Identify whether the input uses the standard or URL-safe alphabet, restore padding when required, and decode bytes before interpreting them as UTF-8 text. Malformed padding, invalid characters, or binary data may produce an error or unreadable output. Do not treat decoded content as trusted HTML, JavaScript, or a file path. Validate the result according to its expected format before passing it to another system.
Why client-side Base64 conversion matters
Encoding and decoding are deterministic browser operations, so a server adds latency and creates an unnecessary copy of the input. Local conversion keeps credentials, file fragments, and test payloads out of a remote logging pipeline. The privacy boundary is clear: browser code can protect the input from this utility's server, but extensions, shared devices, and the destination that receives the decoded value still matter.