Base64 Encode & Decode

No, your data is never sent to any server. All encoding and decoding is processed entirely in your browser using client-side JavaScript, which means your text stays on your device at all times. This is critically important because Base64 is frequently used to encode sensitive information such as API credentials, authentication headers, and JWT tokens. Because nothing is transmitted over the internet, there is zero risk of data interception or unauthorized access by third parties. You can verify this yourself by opening your browser's DevTools Network tab while using the tool — you will see no outgoing requests containing your data. This client-side architecture ensures that even the most sensitive data, including passwords, access tokens, and confidential strings, remain completely safe and private on your local machine throughout the entire encoding and decoding process.

Base64 is a binary-to-text encoding scheme that converts binary data into a sequence of ASCII characters drawn from a 64-character alphabet including A-Z, a-z, 0-9, plus, and slash. It works by grouping binary data into 6-bit chunks and mapping each chunk to a corresponding ASCII character, producing a text-safe representation that can be transmitted over protocols designed for text. This matters because many systems — email servers, HTML attributes, and JSON strings — cannot handle raw binary data directly. For example, when you embed a small image in HTML using a data URI, the binary image data must first be Base64-encoded. However, Base64 increases data size by approximately 33%, so a 3-byte input becomes 4 Base64 characters. It is important to understand that Base64 is encoding, not encryption — it provides zero security and should never be used to protect sensitive information.

Yes, this tool fully supports non-ASCII characters including Chinese, Japanese, Korean, Arabic, and any other Unicode text. It handles this by first converting your input string to UTF-8 bytes before applying Base64 encoding, which ensures accurate round-trip conversion every time. This matters because many online Base64 tools fail with non-ASCII characters, producing corrupted output that cannot be decoded back to the original text. For example, encoding the Japanese greeting produces a Base64 string, and decoding that string returns the original text perfectly. UTF-8 is the dominant character encoding on the web, used by over 98% of websites, and our tool follows this standard to guarantee compatibility. Whether you are working with multilingual content, internationalized URLs, or data containing emojis and special symbols, this tool ensures your encoded data can always be decoded back to the exact original input without any loss.

Base64 is widely used across web development for several critical purposes. The most common use case is embedding small assets like images, fonts, and icons directly into HTML or CSS as data URIs, which eliminates separate HTTP requests and can improve page load performance for small resources. Base64 is also fundamental to HTTP Basic Authentication, where credentials are encoded in the Authorization header, and to JSON Web Tokens (JWT), which use Base64URL encoding for their header and payload sections. Additionally, email systems rely on Base64 through MIME to attach binary files like images and documents to messages. For example, a common pattern is encoding a tiny logo as a data URI in CSS background-image. However, because Base64 increases data size by roughly 33%, it is best reserved for small assets under 10 KB where the request overhead outweighs the encoding cost.