Contact
Corrections, suggestions and questions all go to one address.
Write to hello@stringmash.com. There's no contact form, so nothing you send passes through this site; it goes straight from your email to ours.
What to write about
The most useful thing anyone can send is a correction. If a converter gives a wrong answer or a page gets a fact wrong, say which page it was and what you expected to see, and it will be fixed.
Suggestions for new tools are welcome too. Many of the converters here started as someone asking for an alphabet, a cipher or a calculator the site didn't have yet.
For putting a converter on your own site, the embed page has the code and the rules, and questions about it can come here. Anything about what the site collects is covered on the privacy page, and questions about that come to the same address.