A private portal is only for your team, the people your app signs in with single sign-on, and the readers you add. Everyone else is asked to sign in. Private portals are on the Business plan. Owners and admins set this in Settings → Access.
Make it private
Open Settings → Access.
Under Portal access, pick Private.
It changes straight away. Public is the default: anyone can read the portal, and sign up to post and vote.

A private portal covers your portal's pages, docs, changelog and its feeds, AI answers and the widget. Who can read it:
Your team. They can always read everything.
People your app signs in with single sign-on.
Readers you add by email address or domain, below.
Add readers
With Private picked, Readers lists people outside your team who may read the portal.
In Email addresses or domains, enter up to 20 at once, separated by commas or lines. Use an address like
[email protected], or a domain like@acme.comfor everyone at that domain.Choose Add readers.
Tuti emails each person you added by address a link to the portal's sign-in page, and the message after adding says how many were emailed. People at a domain you added aren't emailed, so tell them yourself.
Readers sign in with their address. An emailed sign-in link works even if they don't have an account yet.
Their address must be verified before they can read. Signing in with an emailed link verifies it.
A domain entry shows "Everyone with a verified @acme.com address".
You can't add a domain anyone can get an address at, like a free email provider. Add people from those one by one.
A portal can have up to 2,000 readers.
Remove takes someone off the list. They can't read the portal until you add them again, and their account stays.
What everyone else sees
Anyone else who opens the portal gets its sign-in page with "… is private. Sign in to see it." Once they're signed in, they go back to the page they were opening.

Signing up is off, and an account that isn't on the list doesn't get in.
Someone signed in with an account that may not read the portal is told they don't have access and can sign in with another account.
Search engines are asked to stay out.
The widget asks visitors to sign in. Your app can sign them in there too. See Sign your users in with single sign-on.
If your app has single sign-on with Your app's sign-in page set, the sign-in page also offers Continue with and your project's name.
Preview it
In Customize, the preview shows the private portal to you as your team sees it.
Some pages for some readers only
To keep the portal public but limit some docs to signed-in readers or certain customers, use Who can read instead. See Choose who can read each page of your docs.
If your plan changes
On a plan without private portals, your portal stays private, but only your team can read it until the plan is back. Your readers are kept. Settings → Access says so at the top, with See Billing.

