Base64 is an encoding scheme that converts binary data or text into ASCII characters safe for transmission through media like email, URLs, or JSON. It is commonly used to store images in CSS/HTML, authentication tokens, and API payloads.
No. Base64 is only encoding, not encryption. Base64-encoded data can easily be decoded without any key. Do not use Base64 to hide sensitive data.
Not at all. The entire encode and decode process happens inside your browser using JavaScript. Your data never leaves your device.
Base64 uses 64 characters: uppercase A–Z, lowercase a–z, digits 0–9, the + and / signs, plus the = character as padding at the end.
Base64 converts every 3 bytes of data into 4 characters, so the output size is approximately 33% larger than the original input.
Decode mode reverses the encoding process — converting a Base64 string back to the original text or data. Useful for reading JWT payloads, inspecting HTTP headers, or debugging API responses.
If the string you enter is not valid Base64, the tool will display an error message. Make sure the string is not truncated and contains no spaces or invalid characters.
This tool only supports text input. To encode image files to Base64, you need a dedicated tool that can read binary files from your computer.
Standard Base64 uses + and / which are not safe to use directly in URLs. URL-safe Base64 replaces + with - and / with _ so it can be used in query strings without additional encoding.
Yes. Base64 Encoder & Decoder is completely free, no account registration, no usage limits, and forever.
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