Free checklist
The 6 checks to run before you build a marketplace
Two of my marketplaces failed for reasons I could have found on paper. This is the list I wish someone had handed me before I built them. Go through it with your own idea. It takes an afternoon.
From Rasmus, founder of Prometora, who learned these the hard way
What's on the list
A short PDF. Page one is the worksheet you fill in for your idea. The next two pages show where each check came from, how to test it this week, and the red flag to watch for.
- 1
Commitments, not compliments
Do you have ten sellers who sent you a real listing, and ten buyers who paid or put down a deposit, before you built anything?
From My Spare Desk
- 2
The substitute test
What does your buyer use today instead, and why is that worse than you? Answer in one sentence.
From My Spare Desk
- 3
Supplier math
Is one transaction worth the seller's time?
From My Spare Desk
- 4
Will the best suppliers join?
The sellers your buyers really want, do they already get enough business without you?
From NinjaBuzz
- 5
Is the demand already searching?
Can you list fifty things your buyers already type into Google?
From NordicMugs
- 6
Do the marketplace math
How many orders a month do you need to make a living, and is that realistic for your niche?
From NinjaBuzz vs NordicMugs
Why I made this
I'm Rasmus. I built My Spare Desk, NinjaBuzz and NordicMugs. Two of them died, for reasons I could have found on paper before writing any code. The third still gets orders every month. I now run Prometora, where hundreds of marketplaces have been built, and the ones that make it all pass these six checks, whether their founders knew it or not.
Watch the full story on YouTubeQuestions about validating a marketplace idea
How do I validate a marketplace idea?
Before you build, check six things: real commitments from both sides, a clear reason buyers would switch, that one transaction is worth the seller's time, that the sellers buyers want will join, that buyers already search for what you offer, and that the numbers add up.
Most of it can be tested in a week with a simple page, a form and a spreadsheet.
How many sellers do I need before I launch a marketplace?
Aim for ten real sellers who sent you a listing and ten buyers who paid or put down a deposit.
Not ten people who said it sounds cool. If you cannot get ten on each side by hand, more features will not fix it.
How do I know if a marketplace idea can make money?
Multiply your average order value by your commission and by a realistic number of orders a month.
If you need thousands of orders a month in a small niche, the idea is in trouble.
The free Prometora revenue calculator does the math for you.
Why do most marketplaces fail?
Usually not because of the software.
They fail because one side never shows up, or because one transaction is too small for the seller or the marketplace to bother.
Two of my own marketplaces failed for exactly those reasons.
Is the checklist free?
Yes.
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Want to run the numbers for check 6 right now? Use the free marketplace revenue calculator, or read the longer guide on how to start an online marketplace.
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Free. It takes an afternoon and could save you a year.