Finding someone interested in cofounding with you is exciting – it’s a bit like dating, where you’ve found a match who’s equally enthusiastic about the journey. But before you “get married” as cofounders, there’s an absolutely crucial process you need to undertake: vetting. This is the due diligence, the getting-to-know-you-on-all-levels process that can make the difference between a harmonious partnership and a disastrous breakup. Having personally vetted and been vetted in the cofounder context, I’ve distilled a step-by-step guide to vetting a potential cofounder in a thorough and thoughtful way.

Why bother with structured vetting? Consider this: up to 43% of founders have to buy out a cofounder due to interpersonal conflicts and misalignment​, often because issues weren’t spotted early. Vetting helps surface those issues before you’re knee-deep in a legal partnership. It’s much easier to walk away from a mismatch at vetting stage than to unwind a company later.

Alright, let’s dive into the steps:

Step 1: Alignment Check – Vision, Values, Goals

Before examining someone’s skills or resume, start with alignment. You want to confirm that you both want to head in the same direction and share core principles. This was discussed in-depth in the article on vision and values, but as a vetting step, it’s about having explicit conversations up front.

• Discuss the Startup’s Vision: Ask each other, “What’s your vision for this venture in 5 years? 10 years?” and compare answers. Do you both see building a global company vs. a small profitable boutique? Are you aiming for a quick flip or a long haul? These need to match. Also, align on mission – why are you doing this? If one is far more passionate about the problem than the other, that could lead to friction.

• Explore Personal Motivations and Goals: Beyond the company, vet the person’s life goals. Do they want to be CEO of a public company one day, or are they serial entrepreneurs likely to jump to the next thing in 3 years? Neither is wrong, but if one of you wants to build the next Apple and the other wants to exit ASAP, that’s trouble. I usually ask, “What does success look like for you personally in this endeavor?” and “How long do you see yourself committed to this project?” It might feel like a wedding prenuptial talk, but it’s necessary.

• Values and Ethics: Pose hypothetical scenarios to gauge values alignment. For example, “If an investor offered us funding at terms that squeeze out early employees’ equity, would you consider it?” or “How should we handle an employee who is talented but creating a toxic atmosphere?” These discussions vet how they think about fairness, integrity, and company culture. You want to discover if you have any fundamental disagreements on how to treat people or conduct business. It’s far better to find out now if your potential cofounder is, say, comfortable with shady growth hacks or not.

Document where you land on these big topics – even if it’s just in notes. If you agree on vision and values, that’s a green light to proceed further. If you find significant divergence, seriously consider whether it’s resolvable. I had a potential cofounder where everything looked good on paper, but during vision alignment, it became clear he envisioned running the business very differently (he prioritized short-term monetization over user experience, almost diametrically opposed to my philosophy). That was a showstopper, and we parted ways amicably then. It saved both of us a potential meltdown later. As startup expert Bryce Conlan noted, team alignment isn’t a nice-to-have – it’s critical​.

Step 2: Deep Dive into Skills and Work Style

Once vision/values are aligned, dig into competence and work habits. Essentially: can this person execute on what they claim, and how do they operate day-to-day?

• Resume and Track Record: Go through each other’s past projects or jobs in detail. Don’t just glance at titles; ask pointed questions. “You led product at X – what was your proudest accomplishment there? What would your teammates say about your contribution?” Listen for concrete results and also clues about teamwork. If possible, discreetly check references or mutual connections. For a potential cofounder, this is not an insult – it’s standard. Maybe you both know someone in common from an industry event – reach out to get informal insight: “Hey, I’m considering working closely with Alex, you’ve worked with them, what’s your take?” A reference check can validate skills and also character. According to one founder’s rule of thumb I admire: “Never skip reference checks on a cofounder, even if they’re a friend.” It’s that important.

• Skill Tests: If your startup requires a specific hard skill (coding, design, finance modeling, etc.), consider doing a brief skill verification. For instance, if they are a developer, maybe review some code they wrote (if you can) or have a trusted technical friend chat with them about system architecture. If they are a marketing person, look at a campaign they ran. You don’t have to “quiz” them aggressively (this is a partnership, not a job hire), but mutual assurance of capability is key. I once asked a tech cofounder candidate if he could build a quick demo of an idea we discussed, just to see speed and style. He did it over a weekend and it impressed me – not just the output, but that he followed through eagerly. It vetted both skill and commitment in one go.

• Work Style Alignment: Vet how you each work. Do you prefer structured planning or a more agile ad-hoc approach? Are you an early bird or night owl? Do you crank out drafts and iterate or perfect things on first go? Share these tendencies. One way to vet this is to collaborate on a small project together (more on that in Step 5, but you can start small even earlier). Another method: discuss past teamwork experiences. “How do you like to structure your workday? When you worked with others, what annoyed you the most? What do you expect from a cofounder in terms of responsiveness and availability?” For example, if one of you expects instant Slack replies and the other checks messages once a day, align that now. Techstars’ cofounder worksheet suggests talking about expectations on things like hours worked, vacation, etc., as these are common tension points​. You don’t necessarily need identical styles, but you need compatible ones or at least awareness to compromise. If I know my cofounder candidate likes to plan meticulously while I wing it, I can adjust or we meet halfway.

• Financial Expectations: Part of work style is how you each handle money and risk. Vet their financial situation and expectations. Are they able to go without salary for a while? If not, what’s the plan? Misalignment here can cause resentment (“He’s not working as hard because he still has a day job” or “She expects me to bankroll her living expenses.”). It may feel personal, but have an open talk: “What’s your financial runway and expectation for salary when we raise money or revenue comes in?” A Carta survey noted 74% of startups have cofounders (not solo), which means equity splits and money are almost always issues to resolve – start early. Perhaps the person has significant debt or obligations that could impede their ability to commit full-time without pay. Better to know now. Also discuss equity expectations frankly (“Do you believe in equal split or something else?”). While you may not finalize numbers at vetting stage, you’ll get a sense if someone feels entitled to a bigger slice – if that’s way out of line with your thinking, it’s a red flag.

Step 3: Small Team Integration – Meet People They’ve Worked With

If feasible, interact with each other’s previous or current colleagues or friends. This can reveal personality and teamwork style in a way talking 1:1 might not.

For example, one step I took was to have a casual dinner with my potential cofounder and one of his former teammates (who I happened to know). That setting let me see how he interacts in a group, how he treats someone who used to report to him, etc. Likewise, I invited him to a group hangout with a couple of my former coworkers. It wasn’t an interview, just social, but you’d be amazed what you can observe: Does the person listen or talk over people? Are they respectful when disagreeing in a friendly debate? Do they show humility or brag nonstop?

Another approach: if your potential cofounder is currently employed or in another project and you can talk to their teammates (with permission), do it. It’s like a backdoor reference. Ask those people about work habits, conflict moments, etc. We often vet employees like this – why not cofounders?

I recall talking to a design lead who worked with my cofounder candidate at a startup. I just wanted an honest take. I learned that my candidate was very good technically (good), could be a bit stubborn on some decisions (noted, but the lead said he improved with feedback), and was very supportive to colleagues (big plus). This gave me a nuanced view and also talking points – I later asked my candidate how he handles being challenged on an idea, noting I’d heard he sometimes held strong opinions. He laughed and explained his side, which matched what the lead said (he used to be more rigid but learned to be more flexible). That actually built trust – he was self-aware and honest about it.

If you don’t have mutual contacts, consider doing something like a personality or working style assessment together (there are cofounder compatibility quizzes out there). Those are imperfect, but they can spark conversations. The goal in vetting is to leave no major stone unturned regarding how this person operates in a team and under pressure.

Step 4: The “What-If” Scenarios and Tough Questions

Techstars’ toolkit suggests addressing “What if a cofounder…?” scenarios to prepare for the future​. This is gold for vetting too. Sit down and run through a bunch of hypothetical tough situations:

• What if one of us wants to quit or take a step back? – How would we handle that? Many don’t discuss this until it happens (bad!). Talk vesting, exit plans, etc.

• What if we wildly disagree on a major strategy and can’t find common ground? – Do we have a mechanism (e.g., an advisor as tie-breaker, domains of authority)? This vets if they’re open to processes and compromise.

• What if a personal life event happens (family, health) that pulls you away? – Would you expect the other to hold the fort? For how long? Is there understanding and contingency for that?

• What if the company runs out of money? – Are you both willing to forego pay, or put in personal funds? It’s critical to gauge risk tolerance and commitment here.

• What if we get an acquisition offer? – At what point (or price) would you be willing to sell? If one says “never, this is my baby” and the other says “heck yes if it hits $X million,” that’s a potential conflict to resolve.

• What if a cofounder is underperforming? – How do we call each other out or redistribute tasks? Are we comfortable having that conversation?

• What if a cofounder engages in misconduct (e.g., lying to investors, harassment)? – It’s dark, but better ask upfront: do we have zero-tolerance on certain things? I’d want to know if someone hesitates on a clear “we’d remove them immediately” in cases of unethical behavior.

• What if our equity split or roles need adjusting later? – Would you ever reconsider who’s CEO or how we divide shares if circumstances change? This vets ego and adaptability.

I know this seems like overkill, but these scenarios flush out expectations. In my vetting, I literally made a list of a dozen “hard questions” like these and we went through them over a few sessions. It was almost like premarital counseling questionnaires. We took notes on answers, and where we differed, we discussed at length. By the end, we essentially drafted a cofounder “prenup” outline. This was immensely comforting – it showed me how we both approach hard decisions. And boy, did those discussions pay off later, because a couple of those hypotheticals (like running out of money) actually happened, and we already knew where each other stood and had a plan.

One key scenario is equity split: People avoid this upfront sometimes, but vetting must include a frank talk on equity division and vesting. How much do each of us feel is fair based on contributions? Do we vest over 4 years with 1-year cliff (standard)? Align on this now. If someone says “I should get 80% because it was my idea,” that might be a deal-breaker unless that truly makes sense. (Usually it doesn’t – execution is everything and idea originators who hog equity often regret it when they end up a solo founder after colleagues leave). There’s data suggesting that teams that split equity equally without discussion often do it to avoid conflict but regret it if contributions differ, and inversely, that equal splits can sometimes deter investors. The point: talk it out and ensure neither of you harbors unspoken assumptions about ownership.

Another often overlooked topic: roles and titles. Vet whether either of you strongly wants to be CEO or a specific title. We naturally fell into our roles by skill, but we explicitly confirmed: “Are you okay if I take the CEO title since I’ll be fundraising mostly?” and “Do you want a C-level title now or later?” It might seem trivial among two people, but clarifying that avoids awkwardness. Some founders don’t care about title, some do – best to know.

Step 5: Trial Project – Working Together Before Committing

This is perhaps the most telling step: actually work together on a low-stakes project before signing any official cofounder agreements. It’s analogous to “try before you buy.”

• Choose a Mini-Project: Ideally something related to your startup (build a prototype feature, conduct a customer survey, co-write a blog or pitch deck, etc.). If your startup is still ideation, even planning an MVP together or doing market research counts.

• Set a Timeline and Goals: Treat it like a sprint. “In the next 2 weeks, let’s accomplish X deliverable together.”

• Observe Dynamics: Pay attention to how you collaborate. Is there clear communication? How do you handle differences in approach? Is one of you procrastinating or pushing too hard? This is where theoretical alignment meets reality. I remember in one trial, my prospective cofounder and I had to solve a technical problem. I noticed he got frustrated quickly when something didn’t work and his communication became curt. It was a bit of a flag for me on how he handles stress. We talked about it afterwards and he acknowledged he had gotten flustered – and usually he had a partner before who took over in those moments. That was insightful; it told me if we worked together, I’d need to be the cooler head in technical crises or we needed a plan for that.

• Assess Enjoyment and Productivity: After the trial project, debrief with each other. How did it feel working together? Did you feel effective? Were there any annoyances? It’s better to surface them now in the spirit of improving teamwork. For us, our trial run building a pitch deck and prototype surfaced that our brainstorming styles were different – I like to talk out ideas, he likes to quietly mull and then present. We found a compromise (set a time for solo thinking, then converge to discuss). Importantly, we both came out of the trial thinking “This could really work, and it was actually fun/exciting.” If you come out thinking “I’m not sure I can deal with this person every day,” that’s telling.

Sometimes, a trial project might reveal a mismatch in skill or commitment – that’s a sign to pause. Maybe they didn’t contribute as much as you expected or vice versa. Have an honest conversation: “I noticed I was the one pushing the project forward. Is there something else on your plate, or are we having motivation differences?” It could be a temporary thing or it could indicate differing levels of devotion.

Think of this step like a probation period. Many startups do a “cofounder dating” phase of a few weeks or months. Don’t rush into equity splits and incorporation until you’ve done this. I know the eagerness is there to formalize once you find someone great, but take a breath and simulate real working conditions first. You might find you collaborate even better than expected (yay, move forward confidently), or discover friction that needs addressing or is unresolvable (in which case, you saved yourself from a premature commitment).

Step 6: Legal and Financial Due Diligence

Vetting isn’t all soft stuff; there’s some hard due diligence too:

• Background Checks: It’s not insulting to do a basic background check. Make sure they don’t have undisclosed legal issues, bankruptcies, criminal records, etc. You can even mutually agree to swap a simple report (especially if either is putting money in). If something does show up, discuss it. Perhaps they had a failed business – not a deal-breaker, but you’d want to hear the story and lessons learned. If they had a legal dispute, get their take. This can actually build more trust if handled openly.

• IP and Non-competes: Ensure they aren’t bringing intellectual property that a past employer could claim, or bound by a non-compete that would jeopardize your startup. If they are leaving a job to do this, vet that they have or will properly handle any contractual obligations. You don’t want to be surprised by a cease-and-desist from their former company. Similarly, if you’re leaving a job, be transparent about your situation.

• Personal Circumstances: While respecting privacy, vet significant life factors: Are they about to move cities? (Remote cofounding can work, but discuss.) Do they have a major life event upcoming (like planning to start an MBA or a family)? None of these are no-gos, but surprises later could strain things. I had a friend who found a cofounder, only to learn months in that the cofounder planned to relocate abroad for personal reasons – something they hadn’t brought up, assuming remote was fine, but it threw off the plan. If vetted earlier, they might have structured things differently.

• Financial Honesty: If either of you is investing capital, open the books to each other to an extent. You should both know what’s going into the company. And if not investing cash, at least confirm that neither has undisclosed debts that could pressure them (they don’t have to show you their bank statement, but a conversation like “Are you financially stable enough to commit full-time for X months?” is fair).

Finally, after all these steps, trust your gut balanced by your data. Vetting gives you data and experience; your gut gives you an emotional read. If everything checks out on paper but you still feel uneasy, explore why. Sometimes intangible personality or trust issues might be nagging you. Conversely, if you feel extremely confident and vetting backs that up with no red flags, you likely have a winner.

Step 7: Make the Decision and Formalize

At some point, you have enough information and trial experience to make a call: do we officially become cofounders?

If yes, congrats – now formalize it:

• Incorporate the company (or add them to the cap table if you already did).

• Sign a cofounder agreement covering equity splits, vesting (please do vesting; standard is 4 years with 1-year cliff so if someone leaves early, they don’t keep all equity), roles, IP assignment to the company, and any special arrangements you agreed on (maybe how disputes are resolved, etc.). There are templates for this, and likely you’ll get a lawyer involved to make sure it’s done right. Formalizing might feel slightly awkward (“we were buddies, now we need a contract?”) but it’s to protect both of you and the business.

• Establish a habit of regular cofounder meetings as you start working officially – keep that trust and communication going that you built during vetting.

If no, or not sure, either extend the trial or politely part ways. It’s okay to say, “I think we’re not the right fit to cofound, but I’d still love to stay in touch or maybe work together in another capacity.” Be gracious; the startup world is small. I had to do this once – the person was disappointed but later thanked me for not dragging them into a misaligned situation.

Remember, not moving forward with a candidate after vetting doesn’t mean they’re a bad person or you wasted time. It means you both saved yourselves from likely failure and can each find more suitable matches. It’s truly like dating in that sense.

In summary, vetting a cofounder is about front-loading the hard conversations and discovery process. It requires a mix of candid dialogue, joint work, reference checking, and gut feeling. It’s some effort, yes, but considering you might spend years and countless stressful moments with this person, it’s a small investment for a huge decision.

Every time I hear of cofounder teams that blew up, I often think, “If only they had vetted that aspect early.” Of course, you can’t predict everything – people and situations evolve – but you can tilt the odds heavily in your favor. In fact, one study of entrepreneurial teams suggests that doing thorough “people due diligence” is as important as market due diligence for success.

By following these steps, you’ll either enter your cofounder partnership with eyes wide open and confidence, or you’ll gracefully avoid a potential cofounder mistake. Both outcomes are wins.

As someone who went through this and ended up with a cofounder I trust deeply, I can attest: the vetting wasn’t always easy or comfortable (we asked each other some tough stuff), but it built a foundation such that once we formalized, we rarely second-guessed our partnership. We knew each other’s strengths, weaknesses, and intentions thoroughly. That allows us now to focus on building the company, not wondering about each other.

So take the time to vet. Your future self (and your startup) will thank you.

Sources:

• Founder misalignment is costly: up to 43% of founders have to buy out a cofounder due to interpersonal rifts​ (hbr.org), often stemming from issues that could be identified with early vetting and alignment checks.

• Techstars recommends addressing “What if” scenarios (cofounder leaves, isn’t delivering, etc.) to prepare for future possibilities​ (toolkit.techstars.com) – these hypotheticals are an excellent vetting tool to gauge compatibility and set expectations early.

• 65% of startups fail due to cofounder conflict​ (entrepreneur.com), underlining the importance of due diligence on cofounder fit. Proper vetting (alignment on vision/values, trial working periods, reference checks) can prevent joining the wrong partner and reduce chances of conflict down the road.

• Don’t rush equity splits: quick, equal splits done without discussion can lead to regret​ (forwardthinking.legal) and even deter investors​ (pubsonline.informs.org). Vet each other’s expectations and agree on a fair split with vesting to protect both parties (common practice per startup legal guides).