Online string encoder and decoder

Convert any text to Base64, URL encoding, HTML or XML entities, a JSON string, hexadecimal or Unicode escapes, and back again with one click.

Your text never leaves the browser: the conversion runs on your device and nothing is sent to any server, so you can paste tokens, test credentials, API payloads or log fragments without wondering where they end up. Before pasting a JWT or an authentication header into the first decoder a search returns, it is worth asking who keeps that text; here the answer is nobody.

It is the everyday Swiss army knife for developers and for anyone fighting with integrations: decode a URL parameter, see what a Base64 value hides, escape a text so it fits inside XML or JSON, or turn a string into hexadecimal byte by byte. The result updates as you type, and «Swap» moves the output back into the input so you can chain conversions.

Type or paste a text to see the result.

Everything is converted in your browser. Gestycontrol never receives or stores your texts.

What each encoding does

  • Base64: turns the text (as UTF-8) into the classic 64 printable characters. You will see it in email attachments, Basic headers or the body of a JWT. The URL-safe variant swaps + and / for - and _ and drops the padding so it can travel inside a URL.
  • URL: good old percent-encoding (%20, %C3%B1) for query parameters and paths. When decoding it also reads + as a space.
  • HTML and XML: escape &, <, > and quotes so the text shows up as written instead of breaking the markup. HTML uses named entities where they exist; XML sticks to the five predefined ones plus numeric references, which is what any XML document accepts.
  • JSON string: gives you the text already quoted and escaped, ready to paste as a value inside a JSON document.
  • Hexadecimal: the UTF-8 bytes in hex, with the separator you choose. Handy for debugging character encoding problems.
  • Unicode escapes: the \uXXXX form used by Java, JavaScript and .properties files.
  • ROT13: the 13-letter rotation. It is not encryption, it only hides a text at first glance.

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