Base64 Encoder / Decoder

Encode text to Base64 or decode Base64 strings back to plain text with UTF-8 support.

The Base64 Encoder / Decoder converts plain text to Base64-encoded strings and vice versa. Base64 encoding is used everywhere — data URIs in CSS, embedding images in emails, API authentication headers (Basic Auth), JWT tokens, and more.

UTF-8 done right

A critical detail: this tool properly handles UTF-8 text. The standard browser btoa() function only works with ASCII characters and will throw errors on Unicode input. This tool uses a TextEncoder/TextDecoder pipeline to safely process any Unicode text, including emoji and international characters.

Common use cases

Whether you’re debugging a JWT payload, preparing a Basic Auth header, inspecting a data URI, or encoding binary data for a configuration file, this tool gives you instant, reliable results without leaving your browser. The bidirectional interface means you can switch between encoding and decoding without navigating to a different tool.

Highlights

Full UTF-8 support — handles Unicode, emoji, and international text
Encode plaintext to Base64 or decode Base64 to plaintext
Proper error handling for malformed Base64 input
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