Sign in with Google
Creating an account and signing in, and what Fermium receives from Google.
Fermium has one way to sign in: a Google account. There is no password to set and nothing to verify by email.
First sign-in
- Go to
fermium.appand click Create account or Sign in. Both lead tofermium.app/app/login. - Tick the box agreeing to the Terms of Service and Privacy Policy. New accounts accept on this screen; see Terms acceptance.
- Continue with Google and pick an account.
- You land in the app. A personal workspace named after your email has been created, or, if your email domain is claimed by a company workspace on a paid plan, you have joined that workspace. See Personal and company workspaces.
Any Google account works: a consumer Gmail address or a Google Workspace account at your company. The email must be verified with Google, which every normal account is.
From an agent
When you authenticate an MCP client (for example /mcp then Authenticate in Claude Code), the browser opens the same sign-in page if you are not already signed in, then a one-time consent page for that client. Creating an account inside that flow is fine; it is the same account you would create on the website.
What Fermium receives
From Google: your email address, your Google account identifier, and basic profile information (name and picture). Fermium never sees your Google password and asks for no other Google scopes: it cannot read your Drive, Calendar or mail.
The Google account identifier is what ties your Fermium account to your Google account. If your email changes at Google, you still sign in to the same Fermium account.
Staying signed in
A successful sign-in sets a session cookie on fermium.app that lasts 90 days. The cookie is host-only, HttpOnly, Secure and SameSite=Lax, so it is not readable by page scripts and not sent from other sites. Signing in on another browser or device creates another independent session.
Rate limits
Sign-in starts are rate limited per IP address. If you hit the limit, wait a minute and try again.
Dedicated instances
An Enterprise dedicated instance can be locked to a single Google Workspace domain. On fermium.app anyone may sign in; signing in never grants access to a document by itself.
Other identity providers
Workspaces on Business and above can connect Microsoft Entra ID, Okta or any OpenID Connect provider for their email domains, optionally making it the only way to sign in for those domains; Enterprise adds SCIM provisioning. If your company has set this up, signing in with Google on a company address takes you to your provider instead. See SSO and SCIM.
A company that has not set this up can still use Fermium with Google accounts, and Restricted documents open for any account they are shared with.