The best place to meet a co-founder isn't a co-founder dating app.

I recruited Harri Thomas as a mentor in the early days of GrowthMentor.

Back then I was messaging people on LinkedIn who had grown the kind of business I wanted on the platform. Harri had bootstrapped a marketplace called Respondent for two and a half years before it raised. Exactly the sort of person I wanted other founders talking to.

We had one call about how marketplaces grow, and I asked him to come on as a mentor.

I did not expect, years later, to be writing about how one of his mentoring calls turned into a company he co-founded with a stranger.

Choosing a co-founder is the highest-stakes decision a first-time founder makes.

And you make it with the least information you will ever have.

You are picking someone to share ownership, stress, and money with for years. Usually off the back of a few conversations.

So it is strange that the standard advice is to go to a mixer, or sign up for one of the many co-founder matching sites, and judge a near-marriage off a first impression.

Case one: a mentor call that became a company

Harri came to GrowthMentor to give back, not to find a business.

On one of his calls, a product engineer named Vito booked him for help with enterprise sales.

Vito is sharp. But by his own description he is a shy guy from a B2B background where the selling was self-serve and automated. You connect people and they come to you.

Enterprise is high-touch and personal. That was the gap he wanted to close.

What happened next was an accident.

Near the end of the call, Harri mentioned he had to jump off to do his quarterly goals review with a few friends. Something he had been doing for over a decade.

Vito stopped him.

Vito turned out to be the only other person either of them had ever met who tracked their life that obsessively.

"It was through that first session with Vito that we created a connection and established a few shared interests, and then we had two or three sessions organized through GrowthMentor before deciding to start a business."

Before they got off that first call, Vito shared his screen and pulled up an immaculate record of his own goals going back eleven years.

They were both repeat founders who had lived all over the place.

From the first design session to a working prototype was about two weeks.

They shared it with the friends they set goals with. Those friends invited a few more. It got posted to a couple of Reddit threads.

Within days, about a hundred people were using a tool that was only ever meant for the two of them.

That tool became Elephants, a social goals app.

The partnership came first. The company fell out of it.

Harri and Vito tell the whole story on Passing the Torch, episode five.

Case two: the mentee who wanted to shut his business down

Etan Efrati joined GrowthMentor as a mentor coming out of six years leading growth at venture-backed startups.

He had built a prioritization framework over those years and never hit pause to write it down. So he used the platform as an excuse to teach it and figure out what he actually knew.

One day he saw a pitch-deck service posted in the GrowthMentor Slack by a designer named Jack Zerby.

The work was so polished that Etan approached Jack, not the other way around.

Jack was drowning.

Etan had given him one idea: run a few webinars with VCs, since their portfolio companies trust them and need decks.

It worked far too well.

Jack closed twelve pitch decks in a single week.

He was charging about two thousand dollars each and working until 2am. He had started to think the whole thing was going to break him.

The first real move Etan made as his mentor was not a funnel or an ad account.

It was to double the price.

Enough breathing room to turn a one-man scramble into a real product.

That consulting relationship became a partnership. A third partner, Sam, runs operations.

Design for Decks is now one of the better-known boutique pitch-deck firms on the internet. Jack runs a distributed team of designers instead of pulling all-nighters alone.

"We've done over two billion dollars raised using Design for Decks designs."

Etan and Jack tell this one themselves on Passing the Torch, episode one.

Why "founder dating" makes me wince

Jack put words to something I had felt for years but never said out loud.

When I first pitched him on GrowthMentor, he told me it sounded like Tinder for startups. I bristled, because that was the one comparison I did not want.

Here is how he frames the alternative now.

"The cringiest thing I can think of is founder dating. I'd never want to meet a business partner at some networking event; that's so forced."

The problem with a mixer is not that the people are bad.

It is that the format shows you the wrong things.

Everyone is on their best behavior. Everyone has a tidy pitch.

And the questions that matter most never come up. How someone treats money. How they hold up under a deadline. Whether they finish what they start.

You leave knowing whether you like someone at a party. Which is a poor predictor of whether you can build with them at 11pm on a Sunday.

Never co-found with someone who has your exact skill

When I asked Jack what made these partnerships hold, he did not talk about chemistry.

He talked about lanes.

His expertise is product and design. Etan's is marketing and distribution. Sam's is operations.

Three defined skills with clean edges. Almost no overlap.

He made the point with a friend named Bobby. A genuinely great designer and a real founder.

Jack said he would never start a company with him. They are both designers. They would spend every day fighting about kerning instead of building.

A co-founder who mirrors your skill set also mirrors your blind spots.

The whole point is to cover ground you cannot.

That is much easier to see when you have built something together than when you have traded backgrounds over a drink.

Suggested mentors

Mentors who have built companies from zero and can talk straight about co-founder fit and the first hard months.

Kosta Panagoulias

Bootstrapped two SaaS products from zero. Building lean with a tiny team.

Book a call

Vas Daskalakis

Startup builder and advisor. Going from an idea to a company that exists.

Book a call

Itay Forer

Serial entrepreneur and startup coach. Co-founder dynamics and early traction.

Book a call

Build the thing before you build the partnership

Both stories run the same way.

Nobody set out to find a co-founder.

Harri set out to help Vito with sales. Jack set out to get help selling pitch decks.

The partnership was a byproduct of doing real work on one specific problem.

That is the part the matching sites cannot give you.

Vito's advice for anyone with an idea is just build it, but do it faster. The way he and Harri built the first Elephants prototype in two weeks, on the side, in the afternoons, until it existed.

So that is the move.

You do not interview for a co-founder.

You find one specific thing worth doing, you do it with someone, and the work answers the questions a conversation cannot.

A task with a clear outcome. Money on the table or not. No expectation that anyone is becoming a partner.

The expectation is the thing that makes a mixer so airless. Take it away and you can actually see the person.

There are a few low-risk ways to set this up. All three show up in these two stories.

• Pay them for a small piece of work. Jack hired Etan as a consultant long before either of them said the word partner. Money on the table makes the expectations honest fast.
• Trade a real favor. Harri mentored Vito on enterprise sales for free. The work was real even though the invoice was not.
• Build a throwaway project together. Elephants started as a two-week side build, no business plan attached. If it is fun to make and it ships, that tells you most of what you need to know.

Suggested mentors

Mentors who can help you build the smallest real version and get it in front of the right people.

Sean Weisbrot

Shipping a real MVP fast, then finding your first users.

Book a call

Daniel Johnson

Go-to-market and growth. Getting an early product in front of people who want it.

Book a call

Vanhishikha Bhargava

Positioning and go-to-market for early-stage products.

Book a call

You do not need to be hunting for a co-founder to use any of this.

A single mentor call is the same move at a smaller scale. One specific problem. One person two steps ahead of you. A real exchange instead of generic advice.

Sometimes that is all you need. Once in a while it turns into something bigger, the way it did for Harri and for Jack.

Jack has a line about this I keep coming back to.

He pays a jiu-jitsu coach a hundred dollars a week. His point: the more you invest in a relationship, the harder it is to walk away from it.

A free piece of advice is easy to nod at and forget.

A standing call with someone who remembers what you said last week, and notices when you are making excuses, is the thing that moves you.

Same logic whether the person becomes a co-founder or stays a mentor. The relationship is the asset, not the single call.

Membership is unlimited calls with any mentor in the network. Bring the same problem to three of them in a week if you want to.

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The pattern under both stories

If you are at the idea stage and wondering whether you need a partner at all, that is a different question. I wrote about what to do first separately.

But if you do want a co-founder, stop looking for one directly.

Find a real problem. Find someone whose skills do not look like yours. Do a small piece of work together before anyone says the word equity.

The partnership, if there is one, will make itself obvious.

I started GrowthMentor in 2018 because I was a non-technical marketer in Athens with nobody to think through problems with. So I built the thing I wished existed.

I recruited Harri to talk to founders about marketplaces.

What came out the other end was a company I had nothing to do with, between two people who would never have met at a networking event.

That is the part I keep noticing.

The best matches on the platform were never trying to match. They were just helping each other with one real thing.

Founders who've built with a co-founder

Before you start the co-founder search,
talk to someone who's been through it.

One call helps you tell the difference between a gap a co-founder fills and one a few hours of the right advice unblocks, and how to vet a partner before any equity gets signed.

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