How 40 Leading Startups Found Their Cofounders
...and how you can find yours. Guest author Palle Broe brings the receipts.
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Today’s essay is a guest post by Palle Broe, cofounder of personalized preventive health platform Hale (now live across the US). For more from Palle, subscribe to his newsletter, Rule of Thumb, and follow him on LinkedIn.
Palle’s done some research on how great cofounders came together. We’ll let him take it from here. —the a16z speedrun team
Finding the right cofounder is one of the most important and difficult steps in building a company. According to Noam Wasserman, the author of “The Founders Dilemma,” It is estimated that 65% of startups fail because of cofounder conflicts so finding the right cofounder is essential.
The process of finding the right person often feels vague and uncertain. In this guide, we’ll explore the most effective ways to meet potential cofounders and share how some of the world’s top startups found theirs.
Specifically we will look into the below:
The six best approaches for finding a cofounder
How 40 leading startups found their cofounder
Technical cofounder spec template
Finding a cofounder is like dating
Finding the right cofounder is a lot like dating. And just like dating, it’s a mistake to focus on one person too early. Unless you already have a cofounder lined up from your previous job or a classmate from university you will need to be prepared to talk to multiple people.
Spending time with 3-5 potential cofounders in parallel gives you contrast. You will learn what kind of profile energizes you and complements your own work style.
You are also likely to experience that potential cofounders will find other cofounders (or ideas) and you want to make sure you are not putting all your eggs in one basket in the early days.
How the leading startups found their cofounders
To back up our advice for how YOU can find the perfect cofounder we looked at 40 leading startups to see how they found their cofounders. We have divided the approaches into five groups:
Classmates
Colleagues
Friend of a friend (or close social network)
Family
Hackathon
Note: One reason “accelerators/startup programs” such as a16z speedrun and YC are not broken out separately in the above list is that in many cases the founders met each other just before applying to those.
The best approaches to find a cofounder
A former colleague/classmate
Nothing beats finding your cofounder through your studies or at work. We are adding classmates and colleagues in the same bucket as a lot of the dynamics are similar.
You’ve already been through deadlines, late nights, and team politics together, which gives you a huge head start in assessing compatibility. You’ve seen each other under pressure, in meetings, maybe even in conflict.
Here’s the top three reasons former teammates or colleagues can be the best cofounders—and how to know if one of them is the right fit:
Trust: You’ve already built a foundation of trust by working together in the past.
You’ve seen how they work: Unlike with a stranger, you’ve witnessed their work ethic, problem-solving style, and ability to execute.
Similar reference frame: Coming from the same environment gives you a common language and similar expectations around communication, culture, and pace. You don’t have to align from scratch if you're already operating on the same wavelength.
A tip here is to proactively look for a cofounder match way before starting a company. Start to figure out who could be a good cofounder for you at work and who might have the entrepreneurial bug in them. Start working on smaller side-projects on the weekends to test it out.
A “friend of a friend”
Some of the best cofounder connections come through second-degree relationships: Not your best friend, but someone they know and vouch for in their network. This allows for built-in social trust, while avoiding the personal baggage that can come with close friendships.
You’re more likely to meet someone with complementary skills, rather than identical ones. And there’s already some vetting done; If a smart friend says, “You two need to meet,” it’s usually worth taking seriously.
The key here is to be intentional. Let your network know what you're working on and that you're open to cofounder intros. Share a one-liner about the idea and what kind of person you're looking for. You’ll be surprised how often someone says, “I actually know the perfect person for this.”
As an add-on, reaching out to VCs can be a great idea - particularly if you have a personal connection to them. They will often have the finger on the pulse on great entrepreneurs who also want to build a company.
Hackathons
Hackathons are one of the best ways to simulate startup life in a compressed timeframe - which makes them a perfect place to meet a potential cofounder. You’re building under pressure, solving problems fast, and seeing how someone codes, collaborates, and communicates in real time.
Why hackathons work:
Built-in time pressure: You get to see how someone handles stress and rapid iteration.
Skill exposure: You watch each other work - not just talk about skills.
Shared experience: Even on a weekend, you can form a strong bond from solving something hard together.
Accelerators/Incubators
A list of companies and organizations are running accelerators and incubators where you are able to meet cofounders. Below are a list of some of the best ones if you are looking for a high-quality cofounder:
Menlo fellowship: A curated group of high-signal founders. Most often at the idea stage or earlier who will often be looking for a cofounder. Menlo helps individuals match with the right cofounder based on the idea space and the competences you are looking for.
YC Directory: Y Combinator’s Cofounder Matching platform is a curated, free matchmaking tool designed to connect aspiring founders with potential co‑founders. Built on YC’s deep expertise in evaluating founding teams, the platform provides access to high-quality, motivated profiles. Over 100,000 matches have been made so far, and several past matches have gone on to be accepted into YC and raise funding.
On Deck Founders (ODF): is a global community and program designed for aspiring and early-stage startup founders to help them ideate, validate, and launch their companies.
Entrepreneur First (EF): A global talent investor that helps individuals find a cofounder and build a startup from scratch. Unlike traditional accelerators that back existing companies, EF selects exceptional individuals before they have a team or idea
Newsletters like Next Play
Some of the best cofounder connections today are being made through curated newsletters, and Next Play is one of the most effective.
Next Play is a private, high-signal newsletter and community for tech operators, ex-founders, and people actively exploring what to build next. Every issue includes updates on who’s leaving their job, who’s looking for a cofounder, and what early-stage ideas are being explored. It’s essentially a “startup talent marketplace” delivered to your inbox.
Why it works:
High intent: People featured are explicitly looking to start or join something.
Shared background: Many come from top-tier startups, VCs, or Big Tech - which helps with trust and alignment.
Link to sign up here
Cold Outreach on LinkedIn
Cold outreach on LinkedIn might feel awkward, but when done right, it can absolutely work. You’ll be surprised by how many people respond positively. LinkedIn is one of the most targeted channels available: you can filter by skill set, location, past roles, and startup experience.
A great strategy is to focus on companies known for strong startup cultures, like Stripe, OpenAI, Ramp, or Anthropic, and reach out to potential cofounders from there.
A strategy that has worked well is to first write an informal message such as:
“Hey X - awesome profile!”
And then once they have accepted the connection write about what you are building:
“Working on a new startup in the x space. I think your profile is a great match and would love to chat.”
References, references, references!
Choosing a cofounder is one of the highest-stakes decisions you’ll ever make, yet many people skip the one step they’d never skip when hiring: checking references. Always, always, always make sure to speak with 2-4 of the cofounders former colleagues. Not just to hear about potential downsides but also to understand how to make your cofounder better and how you will work best together as a team.
2. How 40 leading startups found their cofounders
We looked at how some of the most iconic startups got started. Here are 40 leading startups and how they found their cofounder(s).
3. Specs to find a technical cofounder
Having a clear idea of what kind of cofounder you are looking for is essential.
Particularly if you are a non-technical founder looking for a technical counterpart. As the technical skills required to build a startup will vary from company to company.
We have created a template that you can use to share with potential cofounders to see if there is a match. This one is focused on an AI Engineer. Please remember to adjust pending your role requirements.
Conclusion
Finding the right cofounder is part strategy, part serendipity. The key is to be intentional: explore multiple channels, talk to a lot of potential partners, and be clear about your vision and values.
Don’t wait for a unicorn to fall into your lap. Make it your full-time job to find the right partner to build with. The future of your company might depend on it.
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Loved doing this with you guys 🫶🏼
Amazing piece, thanks Palle 🙏