SlotKeeper

readepub.app › Guides · Updated November 2026

A Google Forms sign-up sheet where full slots disappear

Make one multiple-choice or dropdown question whose choices are the slots, ask for each person's name, and give every slot its own limit with SlotKeeper: a slot is removed from the form a few seconds after the response that fills it. Google Forms alone cannot hide a full slot, so without an add-on you remove it yourself.

Free for one limited question per form, with any number of slots and sign-ups. Pro from $29.99 a year.

Build the form

Who is signing up

Add a required short-answer question for the name. For a reply address, turn on collecting email addresses under Settings, Responses.

One choice per slot

Add a multiple-choice question, or a dropdown for a long list, with one choice per slot. Write the day in each: "Tue 12 Nov, 9:00 to 9:30", not just "9:00".

Say what happens next

Under Settings, Presentation, edit the confirmation message: where to come, what to bring, whom to tell if plans change.

Set the limits

Open SlotKeeper from the form's add-ons menu, tick the slot question, type a limit next to each slot and press Save.

Tips that save trouble later

Without an add-on

There are three ways that use only what Google gives you, each with a catch:

Free and Pro

Free: one limited multiple-choice or dropdown question per form, any number of slots and sign-ups, no time limit and no sign-up. Removing full slots, putting them back, closing the form and the alerts are all free.

Pro, $29.99 a year or $79 lifetime: any number of limited questions, checkbox questions, places left shown in the slot text such as "Tue 9:00 (3 left)", and closing the form after a total number of responses. If a yearly key ends, what is already set up keeps working.

Where the limits are

  • A few seconds of overlap. A slot is removed a few seconds after the response that fills it. Two people who submit within those seconds can both take the last place. SlotKeeper cannot prevent this; it lists the late answers by time in its panel and emails you.
  • Cancellations are not instant. Google Forms has no event for a deleted response, so a freed place comes back at the next submission, at the hourly check, or when you open the panel.
  • About ten limited forms per Google account at once, because of Google's limits on add-on triggers.
  • If an update fails, you hear about it. Google sends no email when an add-on's automatic update fails, so SlotKeeper emails you itself, and an hourly check repairs what it can.

Questions

How do I make a sign-up sheet in Google Forms?

Add a question for each person's name, then a multiple-choice or dropdown question with one choice per slot. To stop a slot from filling past its limit, set a limit per choice with an add-on such as SlotKeeper, since Forms cannot do that by itself.

What do people see when every slot is full?

A question always needs at least one choice, so SlotKeeper shows one line that you word yourself, such as 'No places left'. It can also close the form for you.

Can one person sign up for several slots?

Yes, with a checkbox question, which needs SlotKeeper Pro. Google Forms' own response validation can cap how many boxes one person ticks.

What if someone had the form open before a slot filled?

In our tests, Google Forms refused the removed choice when that person submitted, and asked them to choose again.

Can each slot have a different number of places?

Yes. The limit is set per choice, so one slot can take 1 person and another 20. Choices left without a limit stay open.

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