What viewers see

Viewers need no account and install nothing. They need a browser and access to the inbox of the address they were invited with. This page is written so you can send it to them.

With an invite

Open the link from the invitation email. It goes to the app’s own address, for example https://app.lab.example.com/__hg/accept?…, and shows a Houseguest™ page: Preview of app.lab.example.com, the invited address and when the preview ends.
Press Email me a code. A 6-digit code arrives at that address within a moment. Opening the link alone never uses it up, so link previews in chat and mail apps do no harm.
Enter the code and press Open preview. The app opens in this browser.
Sign in to the app with its own login, if it has one. Houseguest decides who may reach the app; the app still decides what each person can do.

If the person who shared it turned email codes off, step 2 and 3 are a single Open preview button.

The invite then works in this browser only, until the preview ends. In another browser or device, the page says This preview needs an invite: ask for a new link.

With standing access

Open the app’s address, for example https://app.lab.example.com/. A Houseguest page asks for your work email.
Enter your email and press Email me a code. If the address (or its company domain) is on the list, a 6-digit code arrives. The page says the same thing either way, so it never reveals who is on the list.
Enter the code. The app opens on the page you asked for.

A sign-in lasts as long as the person who shared it chose (from 8 hours to 90 days, or until the preview ends). After that, the same page asks for a new code.

With single sign-on

When the workspace that shared the app uses single sign-on and the address belongs to its company domain, the page shows Continue with single sign-on in place of the code: it opens the company’s usual sign-in page and comes back to the app. Email me a code instead may also be offered, unless the company requires single sign-on.

With a Microsoft account

The sign-in page may also show Sign in with Microsoft, in place of typing a code. It opens Microsoft’s sign-in page, where you pick a work, school or personal Microsoft account, and comes back to the app.

The account’s email address must be the invited address (for an invite) or one on the list (for standing access), exactly as with a code. Another account is refused.
Microsoft must confirm the address. Personal accounts (Outlook.com, Hotmail, Live) always qualify. A work or school account qualifies when its organization owns the address’s domain; otherwise the page says Microsoft does not confirm the address, and the email code still works.
Where the company that shared the app requires its own single sign-on for your address, only that is offered.

Codes

A code works for 10 minutes and allows 5 wrong tries.
Send a new code works after 30 seconds, up to 5 codes an hour.
Codes come from Houseguest, under the name of the workspace that shared the app. If none arrives, check the spam or quarantine folder.

Pages a viewer might see

Page	Meaning	What to do
This preview needs an invite	This browser has no sign-in for the preview	Open the invite link in this browser, or ask for a new one if it was used elsewhere
This invite link no longer works	The invite was used, expired, or was revoked	Ask the person who shared it for a new one
This preview opens time	The preview is scheduled	Come back at that time. The invite link keeps working until it is used
This preview has ended	Its time ran out or it was closed	Ask the person who shared it
No preview is open here	Nothing is shared on this address right now	Check the link in the email
The app is not reachable right now	The preview is open, but the connection to the app’s network is down	Try again in a minute; tell the person who shared it if it persists
This preview is not available	The workspace that shared it is paused	Ask the person who shared it
This preview has reached the number of people it can have	The preview is full	Ask the person who shared it
Too many codes from this network	Many code requests from one network in an hour	Wait an hour

Times on these pages are in UTC.

Signing out

Visiting /__hg/signout on the app’s address signs this browser out of the preview. An unused invite link can bring you back; a used one cannot.

SSH and other services

If the preview includes SSH or a database, the preview page or the person who shared it gives the commands. See TCP and SSH.