Bug reports, wrong answers, and requests for tools that do not exist yet.
One address for everything: sunfei0318@gmail.com. It is read by a person, not an autoresponder.
Reporting a wrong answer
These get the fastest response, because a calculator that returns the wrong number is worse than no calculator at all. To make it quick to fix, include:
- Which tool, and the link to it.
- The exact input you entered.
- What you got, and what you expected instead.
- What you are checking it against, if anything.
Requesting a tool
Requests are genuinely the main driver of what gets built. Say what you are trying to work out and how you currently do it — the problem is more useful than the proposed solution. If a tool already exists that nearly does it, say what it is missing.
Reporting a bug
For anything that breaks rather than computes: which browser and version, and what you did immediately before it went wrong. A screenshot helps if the layout is the problem.
Privacy and data requests
Questions about what the site collects, or a request relating to your personal data, can go to the same address. See the privacy policy first — it will usually answer the question, since the site collects very little by design.
What not to send
Please do not email real passwords, private keys, access tokens or anything else sensitive in order to demonstrate a problem. Describe it, or use a throwaway value — the tools never send us your input, and email is the one place where it would actually leave your machine.