Fake Door Test: Measure Demand Before You Build
A fake door test shows buyers an offer for a product that doesn’t exist yet, a page or a button with a real price, and counts how many try to buy or sign up. When someone clicks, you tell them it’s coming and invite them to a waitlist or a pre-order. It measures demand with actions instead of opinions, in days and for the cost of a page and a small ad budget. Set the number that means go before you start.
What is a fake door test?
The “door” is any entry point to the product: a landing page, a pricing button, a menu item inside an app you already run. Behind it there is no product yet, only a short message:
“Thanks for your interest. [Product] isn’t ready yet. Leave your email and you’ll be first to get it, at the launch price.”
Every click on the door is a buyer saying “I want this at this price” with their behavior. That is worth more than any survey answer, because saying yes to a survey costs nothing.
The same idea goes by other names. A smoke test usually means a landing page plus traffic to check demand. People also say landing page test, naming it after its tool. A pre-order test goes one step further and takes payment or a deposit.
When should you run a fake door test?
Run it after the cheap desk checks and before you build, because each stage costs more than the one before it:
| Stage | The question | The test |
|---|---|---|
| 1. Desk research | Is the pain real and does anyone pay? | Read threads, competitors, ads and prices |
| 2. Fake door | Will buyers try to get your offer? | A page with a price and a button |
| 3. Pre-order | Will they actually pay? | Take payment or a deposit before you make it |
| 4. MVP | Does the product keep them? | A minimum viable product |
A fake door can’t tell you whether the problem exists. If nobody talks about it, a page with a button only proves that slowly and with ad money. Start with how to find pain points on Reddit and how to find competitors for a product idea.
How do you run a fake door test, step by step?
- Write the promise in one line. Who it’s for, the result, how. Use the words buyers use for the problem.
- Set a real price. Anchor it on what buyers already pay; how to price a new product covers the method. A test without a price measures curiosity.
- Build one page. A headline, three or four lines on what it does, the price and one button (“Get early access at $X” or “Pre-order”).
- Write the honest message behind the button. Say it’s not ready, say when you expect it, and offer the waitlist or a refundable pre-order.
- Decide the go number before you start. For example, a click rate on the button and a cost per waitlist signup you can live with.
- Send real buyers. A small ad budget aimed at the buyer, or posts where they already gather. Friends don’t count.
- Read the result against the number. Then follow up with the people who signed up: a short reply from them tells you why they clicked, in their own words.
What number means go?
There’s no universal rate, because it depends on the price, the traffic and how warm the audience is. What matters is that you write your number down before you look. Some useful ways to set it:
- From your costs. If a customer is worth $X to you, a waitlist signup has to cost well under that.
- From comparison. Run two versions of the page (two angles, or two prices) with the same traffic. The winner is the direction to build.
- From intent. Pre-orders and deposits outweigh emails, because money is harder to give than an address. Ten paid pre-orders say more than a hundred free signups.
If the result misses, change one thing (the angle, the price or the audience) and run it again. Changing everything at once tells you nothing, since you can’t see which change moved the number.
Is a fake door test honest?
It is, when you treat the people who click with respect:
- Say clearly, right after the click, that the product isn’t available yet.
- Never take payment for something you can’t deliver without saying so; pre-orders should say the expected date and be refundable.
- Use the emails only for what you said: the launch.
- Don’t leave a fake door running for months inside a product people pay for. Answer it with a decision.
FAQ
How much does a fake door test cost?
The page can be free to make. The real cost is traffic: a small ad budget for a few days, or the time to post where buyers gather.
How long should it run?
Until you reach the number of visitors you decided in advance. A handful of clicks is noise.
Can I run it without ads?
Yes, with posts in communities where the buyer already is, as long as the rules there allow it. It’s slower and the numbers are rougher.
What’s the difference between a fake door and an MVP?
A fake door has no product behind it; it measures interest in the offer. An MVP is the smallest product that works; it measures whether buyers keep using and paying.
Check the idea before the door with Vettoz
Vettoz runs the desk check that comes before a fake door, inside Claude, ChatGPT or Cursor. For one idea he reads Reddit threads and comments, X posts, TikTok and YouTube videos, active Meta ads, Google, and TikTok Shop or the App Store depending on the kind of product. He scores pain, demand, pay, room and reach from 0 to 100, with a GO, TEST or RETHINK verdict, and your AI writes the report with every source linked. He also scores the positioning angles you want to test, and with a full idea your AI writes three Meta ads that he renders in your brand, so the test traffic has ads ready to run.
Your first 2 checks are free, no card. Packs of 1, 4 or 15 ideas are one-time payments that never expire. To try it, connect Vettoz to your AI and type “check this idea with Vettoz” with your idea in one sentence. You can also see how it works or compare the packs first.