About string.is

string.is is an open-source, privacy-friendly online string toolkit for developers.

It is intended to be a safe alternative to pasting sensitive data into third-party online tools.

The ideal conversion tool should have the following features in order to protect the privacy of its users:

  1. It should be open-source.
  2. It should not set any cookies.
  3. It should have a strict Content Security Policy.
  4. It should be extremely opinionated about dependancies, and only use well-known, well-supported libraries.
  5. It should try to detect the format of the input, and intelligently choose output options.

string.is was built to meet those goals, and provide a secure, trustworthy string conversion tool.


  • DevUtils by Tony Dinh is a great open-source MacOS desktop tool.
  • DevToys by Etienne Baudoux is an open-source Windows desktop tool which looks very good, although I haven't tried it.
  • CyberChef by the UK’s GCHQ provides an exhaustive set of conversion and crypto tools, and works both online and offline.


string.is wouldn’t exist without the following open-source libraries:

The icon is based on developer by Achmad Mulyana.