A marketplace with three listings and no traffic has nothing to sell a consumer, and no volume of clever email fixes that. Nobody signs up to browse an empty shelf, and writing a better subject line about an empty shelf doesn't change what's on it. This is the honest starting point for a two-sided marketplace: one side of your cold-start problem is not a sales problem, and treating it as one wastes the exact weeks you need for the strategy that actually works.
Say plainly which half this doesn't fix
If your marketplace connects consumers to something, buyers to sellers, renters to hosts, diners to a table, cold outbound cannot manufacture the consumer side. Demand-side liquidity for a two-sided marketplace is a product and incentive problem: a single-player mode people use even with nobody else around, a manual concierge matching the first hundred requests by hand, a narrow geography or niche small enough to feel full instead of empty. None of that is something an email finds you, and it would be dishonest to imply otherwise. If your plan for getting your first users was going to be a cold email campaign to consumers, that plan needed to change before this paragraph, not because of anything this product does or doesn't do, but because that has never really worked for anyone.
The other side is usually a business, and businesses are exactly what this is for
Here is the half that does fit. Most two-sided marketplaces have a supply side made of businesses: contractors, vendors, independent providers, small shops, freelancers, property owners, whoever is providing the thing being matched. A business is describable by industry, size, and geography the same way any B2B buyer is, which means it's countable and reachable the same way any B2B buyer is. Recruiting the first wave of supply, the listings that make the marketplace look alive to the very first visitor, is a genuine cold outbound problem, and it's the lever that actually starts the flywheel, because supply can exist and look credible before there is a single consumer to serve it.
This reframes the whole cold-start question usefully. The order isn't "get users, then get sellers to follow." It's "get enough real, credible supply that the first handful of consumers who do show up, through whatever wedge got them there, find something worth staying for." Outbound's job in a marketplace is almost always on this side of the equation.
Sizing the supply side before promising anyone a launch date
Describe the business you need as supply the same way you'd describe any B2B buyer: industry, size, location if it matters to the match. Rocketship gives back the real number for free, along with twenty-five of the actual businesses by name, no charge either way. This answers something marketplace founders often guess wrong: whether enough qualified businesses actually exist in the first target geography to make the marketplace feel populated on day one, or whether the honest number means widening the region before attempting a launch at all.
The phone matters more here than most supply-side founders expect
A business deciding whether to list on a brand-new marketplace usually has questions before it commits: how payment works, what the commission is, whether customers are actually going to show up. Some of them email. A meaningful number of them just call the number on the site, because that's how they already do business, and a business owner sizing up whether to trust a new platform is exactly the moment they want a real answer, not a voicemail greeting. Missing that call doesn't just lose one applicant. It loses one listing at the exact stage when every single listing matters, because there are only a handful of them.
The questions themselves are almost always the same three: how the commission gets calculated, when payouts actually happen, and whether the platform will send them any real customers at all. Answering those three plainly, out loud, whoever or whatever is doing the answering, converts more hesitant applicants into live listings than a well-designed FAQ page nobody reads before picking up the phone anyway.
What a real first cohort looks like in numbers you can check
Say the target is a single metro area and the category needs roughly fifty active listings before the marketplace stops feeling empty to a new visitor. If the free count for qualifying businesses in that metro comes back at six hundred, that's a workable ratio: you need to convert something like one in twelve. If it comes back at forty, the geography is too narrow for the model and needs widening before anything else happens.
A business added to the outreach list runs one credit, and finding a verified phone number or email for it runs five, charged only where one is actually located. A hundred credits ride along with Launch — just under twenty-five dollars monthly — plus one worker running the outreach and follow-up with that supply-side list, and a line answered around the clock for businesses calling in with questions before they commit. That hundred-credit allowance is enough for a real first pass at a metro-sized list of supply, with some left to pull verified details on whoever looks most likely to say yes. Once recruitment is running across more than one geography or category at a time, Frontier's seventy-nine dollars covers a second worker and the scheduler that paces them both. At a hundred and forty-nine dollars, Mission Control moves to three simultaneous workers with no limit on the apps built alongside them, which fits a marketplace pushing into several metros or verticals together.
Keep the two problems separate on purpose
Solving supply-side cold start does not solve demand-side cold start, and it was never going to. What it does is give the consumers who do arrive, through whatever wedge actually gets them there, something real to find when they show up. That's the honest scope of what outbound does for a marketplace: it fills the shelf. Filling the store is still a different job, and no amount of well-targeted email substitutes for it.