Encoder / Decoder
Base64, URL and HTML encode/decode.
Your text is processed entirely in your browser — never uploaded or stored.
What is this tool?
The encoder / decoder converts text between Base64, URL (percent) encoding, and HTML entities — handy for API work, data URIs, query strings and safely showing code in posts. Pick a type and direction, then press Run.
What each type does
- Base64: encodes text as UTF-8 bytes into 64 characters via
btoa(unescape(encodeURIComponent(str))), decoding in reverse, so Korean and emoji stay intact. - URL (percent): turns spaces and special characters into
%XXusingencodeURIComponent/decodeURIComponent. - HTML entities: converts
& < > " 'to named entities; decoding also handles numeric entities like'.
Note: Base64 is not encryption — anyone can decode it, so never use it to protect secrets.
Privacy & processing
Everything runs in your browser. Your text is never uploaded or stored, and you can copy the result to your clipboard.
FAQ
What is Base64?
Base64 represents binary data or text using only 64 characters (letters, digits, '+' and '/'). It is used to carry data safely where only text can be sent — email attachments, data URIs, tokens. It is not encryption, so anyone can decode it back to the original.
When do I use URL encoding?
URL (percent) encoding lets you put spaces, Korean or special characters like & and ? into a URL or query string. A space becomes %20 and Korean becomes UTF-8 bytes such as %EA…. It is needed when passing search terms or parameter values safely.
What are HTML entities?
HTML entities replace characters with special meaning in HTML — <, >, &, " — with codes like < > & " so they display literally or to prevent code injection (XSS). Decoding restores both named and numeric entities (e.g. ').
Is Unicode such as Korean handled safely?
Yes. Base64 encoding first converts the string to UTF-8 bytes with encodeURIComponent, and decoding reverses it, so Korean and emoji are never corrupted. URL and HTML processing also work on UTF-8 and round-trip exactly.
Is my text sent to a server?
No. All encoding and decoding happen in your browser; your text is never uploaded or stored, so you can safely convert tokens or private strings.
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