Base64 Decode

The Base64 Decoder converts Base64-encoded strings back into their original plain text. Base64 is a binary-to-text encoding scheme that represents binary data using a set of 64 printable ASCII characters. It is widely used in web development to embed images as data URIs, transmit binary data in JSON and XML payloads, encode email attachments via MIME, and store authentication tokens and API keys in configuration files.

When you receive a Base64 string from an API response, a configuration file, a data URI, or an encoded email header, this tool lets you instantly see the original content. Paste the encoded string and the decoder converts it back to readable text in real time. The tool correctly handles Unicode content by first decoding the Base64 string to its raw byte representation and then interpreting those bytes as UTF-8 text using the TextDecoder API. This means it works reliably with text in any language, including characters outside the basic ASCII range.

If the input is not valid Base64, the tool displays a clear, friendly error message instead of crashing or producing garbled output. Common issues include extra whitespace, line breaks, or characters that are not part of the Base64 alphabet. The error message helps you identify and fix the problem quickly.

Base64 decoding is a routine task for developers debugging API integrations, DevOps engineers inspecting configuration values, security analysts examining encoded payloads, and anyone who encounters Base64 strings in their daily workflow. All processing runs locally in your browser, so sensitive data such as tokens or credentials is never sent to any server.