What is a Fake Door Test?
A fake door test (also called a painted door test) puts a button, menu item or link for a feature that does not exist yet into a place where real people already are: your website, your app, your shop or your newsletter. When someone clicks, they see a short, honest message that the feature is coming, and you count the clicks. The click is the data. People vote with their finger in the middle of a real task, which beats asking them in a survey whether they would like the feature.
The difference from a landing page test: a landing page tests a whole product on strangers you have to bring in. A fake door tests ONE addition on people who are already using something of yours. That makes it cheap, fast and very precise, and it needs existing traffic.
When should you use it?
Use it when:
- You already have a website, app, shop or newsletter with at least a few hundred visitors or readers a month.
- You are choosing between features, add-ons, a premium tier or a new product line, and your gut keeps changing its mind.
- The thing would take weeks to build, so a wrong guess is expensive.
Skip it when you have no audience yet (start with a landing page), when the feature is a legal or safety requirement you must build anyway, or when the click would mislead people about money, say a fake “Buy now” that seems to charge their card.
How do you do it, step by step?
-
Write the decision and the line before you build anything. One sentence: “If at least X% of people who see the button click it within 14 days, we build it. If fewer, we drop it.” Our rule of thumb for an in-product feature: 3% to 5% of exposed users clicking is worth a closer look, above 8% is strong. Write the number down now, because after the test every number looks good.
-
Put the door where the need happens. A “Download as PDF” button belongs right next to the thing people would download. A premium tier belongs on your pricing page next to the free plan. Place the door at the moment of need, or you measure how well you hid it.
-
Label it like a real feature. Use plain words and the same style as your other buttons: “Send automatic reminders”, “Add a second location”, “Get it printed and shipped”. Avoid “NEW!” badges, since they pull clicks out of curiosity and inflate the result.
-
Write the honest message people see on click. A small pop-up or page: “We’re building this right now and you’re one of the first to ask for it. Want early access? Leave your email and we’ll tell you the day it’s live.” Add one optional question: “What would you use it for?” A free Tally form embedded in the pop-up handles both. Never show an error message or pretend the feature broke.
-
Track two numbers: exposures and clicks. An exposure is a person who saw the button. In PostHog or Google Analytics 4, send an event when the page with the door loads and another when the button is clicked. Click rate = unique clickers divided by unique people exposed. Counting clicks without exposures tells you nothing.
-
Run it for a fixed window. Our rule of thumb: until at least 300 people have seen the door, or 14 days, whichever comes later. Weekends and paydays shift behaviour, so cover at least one full week.
-
Close the door and follow up. Remove the button when the window ends. Email every person who left an address: thank them, say whether you are building it and when. Book a 15-minute call with three of them to hear what they expected behind the door.
What does a worked example look like?
Say Marta runs a free website with invoice templates for freelancers. About 3,000 people a month download a template. She wonders whether to build a paid add-on that sends automatic payment reminders to clients for €4 per month.
Her line: 5% of people who see the button click it within 14 days. Next to the “Download template” button she adds a second button: “Send automatic payment reminders (€4/month)”. Clicking it opens a Tally form: “Reminders are coming soon. Want early access? Leave your email.”
After 14 days, 1,900 people saw the button and 171 clicked it: a 9% click rate. 64 left an email and 12 wrote what they would use it for. Eight of those 12 said “clients who pay 60 days late”, which gives Marta the headline for her real launch. She also learns something uncomfortable: designers clicked at 14%, developers at 3%. Designers get the feature first.
Which free tools help?
| Tool | What you use it for | Free plan |
|---|---|---|
| PostHog | Tracking door views and clicks as events, funnels | Yes, with a monthly free allowance |
| Google Analytics 4 | Event tracking if your site already uses it | Free |
| Google Tag Manager | Adding click tracking without touching your site code | Free |
| Tally | The coming-soon pop-up form with email and one question | Yes, unlimited forms and submissions |
| Microsoft Clarity | Watching recordings of how people reach the door | Free |
What mistakes should you avoid?
- No exposure count. “47 clicks” means nothing until you know whether 200 or 20,000 people saw the button.
- A door nobody can find. A low click rate on a hidden button is a placement problem dressed up as a demand answer.
- Taking payment for nothing. Never charge a card for something that does not exist. If you want to test willingness to pay, show the price on the button, then send people to an honest message.
- Leaving the door up for months. Every click after you have your answer is a small disappointment. Close it on schedule.
- Ignoring the people who clicked. They raised their hand. If you never write back, you burn the goodwill you need at launch.
How do you know it worked?
The test worked when you hit the line you wrote in step 1 AND at least a few clickers explain in their own words what they would do with the feature. A high click rate with zero emails points to curiosity. A modest rate with detailed answers points to a real, narrower need.
Go: you passed your line and the reasons match. No-go: you missed the line by a wide margin, even after checking the placement. Retest: you are close to the line and the door was hard to see.
What should you do next?
If people want the feature, check what they will pay with price testing, then follow the clickers through your conversion funnel once it is live. If you had no audience to test on, go back to an assumption map and pick a test you can run on strangers. You can also practise designing tests like this with an AI co-founder in the F/MS startup game.
FAQ
Is a fake door test ethical?
It is when the message on click is honest, you never take money, and you remove the door within a few weeks. Telling people “this is coming, want early access?” respects their time. Showing a fake error or a fake checkout does not.
What is a good click rate for a fake door test?
There is no universal number, because it depends on placement and audience. Our rule of thumb for a feature button inside a product is that 3% to 5% of exposed users deserves a closer look and anything above 8% is strong. Set your own line before you start.
What is the difference between a fake door test and a landing page test?
A fake door tests one addition on people already using your site or product. A landing page test checks a whole new product on strangers you send to a separate page. Use the landing page when you have no audience yet.
Updated 26 October 2026 · Written by the Fe/male Switch team