For a two-sided marketplace, which side would you solve first?

One of the hardest parts of building a marketplace isn’t building the product. It’s deciding which side needs to exist first.

I’m working on a marketplace where one group has unused capacity and another group is looking for access to it.

The obvious answer is: get supply first. Without listings, buyers arrive and see an empty marketplace.

But there’s a catch.

If you recruit suppliers before there’s demand, they list something, wait, get no activity, and may never come back. You haven’t really solved the cold-start problem — you’ve just moved it to the other side.

I’ve been thinking about three approaches:

Supply first. Build enough inventory that the marketplace feels useful before bringing in buyers.

Demand first. Find people actively looking for something, then recruit supply specifically around what they’re asking for.

Start narrow. Pick one category or use case where you can manually create enough liquidity on both sides, then expand.

The third approach feels increasingly compelling to me. A small marketplace that works might be more valuable than a broad marketplace that looks empty.

For founders who’ve built two-sided products: which side did you seed first, and would you make the same choice again?