Developer utility

Base64 online

Кодирование и декодирование Base64 прямо в браузере — данные не отправляются на сервер

Text

Base64

The result will appear here

About Base64

Where it is used

  • • Data URIs for images and fonts in HTML/CSS
  • • Passing binary data in JSON and APIs
  • • Email attachments (MIME)

Good to know

  • • It is encoding, not encryption
  • • Increases data size by ~33%
  • • Everything is computed locally in your browser

Base64: why and where it is used

Where you meet Base64

Data URIs for embedding images and fonts directly in HTML/CSS, encoding email attachments (MIME), passing binary fields in JSON and APIs, basic authorization in HTTP headers.

The tool works correctly with Cyrillic and emoji thanks to pre-encoding into UTF-8, so Russian text is encoded and restored without distortion.

Worth remembering

Base64 increases data size by about 33% — you should not overuse data URIs for large files, as it slows down page loading.

For a webmaster, Base64 is handy when debugging tokens and webhooks and setting up integrations where values are passed in encoded form.

Frequently asked questions

What is Base64?+

Base64 is a way to represent any binary data using a set of 64 printable ASCII characters. It is used to safely transfer data where only text is allowed: in JSON, URLs, email, data URIs and headers.

Is the data sent to a server?+

No. Encoding and decoding are done entirely in your browser in JavaScript — the entered text is not transmitted anywhere, so the tool is safe even for sensitive data.

How is URL-safe Base64 different from regular?+

In the URL-safe variant, “+” and “/” are replaced with “-” and “_”, and the “=” padding is often dropped. This lets the string be used in URLs and file names without extra escaping.

Is Base64 encryption?+

No. It is reversible encoding, not encryption: anyone can decode the string back. Do not use Base64 to protect passwords or secrets — that requires hashing or encryption.