mattslyonCharacter LabmattslyonFollow @mattslyon

Privacy

What this site keeps

Last updated 25 August 2026

The Character Lab is a small fan project. There are no accounts, no sign-ups, and no profiles, so there is not much to say here. That is deliberate.

What is stored

When you create a character, the server writes one record containing:

  • the premise you typed, and the character written from it
  • the time of the request
  • your browser’s user agent string, used for debugging
  • which AI model ran and how many tokens it used, so the running cost can be tracked

If you use the share button, the premise and character are also saved as a share page with its own link.

What is not stored

Your IP address is never written down. Neither is your city, your country, nor any other location. Nothing you type is connected to you, because nothing identifying you is kept beside it.

An earlier version of this site looked up each visitor’s IP address and approximate location through outside services. That was removed, and those requests no longer happen.

How abuse is stopped without keeping an address

The server does have to stop one person from running up the bill. To do that it reads your IP address, reduces an IPv6 address to its network block, combines it with a fixed secret, and stores only the resulting hash — a fixed-length string that cannot be turned back into an address. That hash counts your requests for one hour and is attached to nothing else: not your premise, not your character, not any other record.

Who else sees a premise

  • Google, through the Gemini API. Each premise is sent to Google twice: once to screen it, and once to write the character. Google states that prompts sent through the paid Gemini API are not used to train its models.
  • Google Firebase. Hosting, the database, and the server functions all run on Google Firebase, in the United States.
  • Google Analytics for Firebase. The site measures traffic with Firebase Analytics. This one is worth reading twice, because it works differently from everything above: it stores an identifier in your browser, and Google derives an approximate location from your IP address on its own systems. That information is held by Google under its privacy policy, not by this site, and this site never sees your address or your location.

Share pages are public

A share page can be opened by anyone holding its link. It is marked so search engines do not index it, and it is not listed anywhere on this site, but a link is still a link. Treat anything you share as public.

How long any of it lasts

Generation records are kept while the lab is running, so usage and cost can be monitored. Share pages stay up until they are removed.

Having something removed

Email privacy@welzware.com with the share link, or with the premise and roughly when you created it, and it will be deleted. There is no account to look you up by, so a link is by far the fastest way to find something.

Children

This site is not directed at children under 13, and no information is knowingly collected from them.

Changes

If any of this changes, the date at the top changes with it.

See also the terms of use.

Fan-made character lab inspired by mattslyon. Not affiliated with or endorsed by him.

Designed and built by Welzware.

PrivacyTerms