What Is Base64 Encoding?
Base64 is a binary-to-text encoding scheme that represents binary data using 64 ASCII characters. It is commonly used to embed binary content inside text-based formats such as JSON, XML, email attachments, and data URLs. A Base64 encoder converts plain text into this safe character set, while a Base64 decoder reverses the process to recover the original data.
Why Use Base64?
Many protocols only allow printable ASCII characters, so sending raw binary directly can corrupt the data. Base64 solves this by expanding every three bytes of input into four printable characters. This makes it perfect for embedding images in HTML and CSS, encoding credentials for HTTP basic authentication, and transmitting data through channels that reject special characters.
UTF-8 Support Matters
A common mistake is encoding text with the btoa function, which only handles Latin-1 characters. If you encode emoji or accented characters this way, you will get an error or wrong output. A proper Base64 encoder and decoder first converts the string to UTF-8 bytes, which preserves every character correctly.
When to Encode and Decode
- Embedding small images as data URLs
- Passing binary data through JSON APIs
- Encoding credentials for authentication headers
- Inspecting or debugging encoded payloads
Base64 is not encryption and provides no security, so never use it to protect sensitive data. If you need to hash values instead, use our MD5 hash generator, or prepare strings for the web with the URL encoder decoder.