People ask a lot of questions when you start a company. What’s the idea? Who are the customers? Are you raising money?
They rarely ask the question that matters most in the first few years: who are you building it with?
A startup is a long, uncertain, stressful project. Your co-founder is the person you’ll spend most of your waking hours with, argue with, celebrate with and, on the bad days, depend on completely. Investors know this. Many of them say they bet on the team more than on the idea, because ideas change and teams mostly don’t.
I’ve now co-founded two businesses with two very different partners.
- Santara, an AI product for short-term rental hosts, with a former colleague.
- HiTaVa, a spreadsheet-template business for small companies, with my girlfriend, who runs almost everything there day to day.
These are two very different kinds of partnership. This post is about what I looked for in each, what we put in writing, and what I’d tell anyone about to say yes to a co-founder.
Why not go alone?
First, the obvious question. Why have a co-founder at all?
Some people build great companies alone. It can be done. But for me, three reasons made a partner feel essential.
There’s too much to do. A young company needs someone building the product, someone talking to customers, someone selling, someone handling money and paperwork. One person can cover all of that for a while, badly. Two people can cover it much better.
You need someone to tell you you’re wrong. When you work alone, every idea sounds good at 1 a.m. A co-founder who cares about the company as much as you do is the fastest way to find out which ideas are bad, before customers do.
It’s lonely. Founders don’t talk about this enough. Most of the time, nobody tells you if you’re doing well. A co-founder is the one person who fully understands what you’re carrying, because they’re carrying it too.
So the question was never really “co-founder or not.” It was “who?”
Santara: building with a former colleague
I didn’t start Santara with someone I met at a networking event. I started it with someone I had already worked with. I wrote about that decision briefly in Nothing Was Wrong. That Was the Problem., and I want to go deeper here.
What working together already told me
Working together in a normal job is not the same as running a startup together. But it shows you things that no coffee meeting can.
How they behave under pressure. You’ve seen them when a release breaks at the worst moment, when a deadline moves, when a client is angry. Do they panic? Blame someone? Go quiet? Or do they start fixing things?
How they disagree. Every team argues. What matters is how. Can you push back on their idea without it becoming personal? Can they say “you’re right, I was wrong” out loud? Can you both disagree hard in the afternoon and work normally the next morning?
How they treat people. Watch how someone treats the junior engineer, the tester who found their bug, the person who can’t do anything for them. That’s how they’ll treat your first employees and your customers.
Whether they finish things. Lots of people start things. Fewer ship them. In a startup, finishing is everything.
When I thought about starting a company, I didn’t make a list of skills first. I asked myself: who have I seen at their worst moment and still wanted to work with afterwards? That’s a short list. It made the decision much easier.
What working together didn’t tell me
I also tried to be honest about what I didn’t know, because a shared job hides some things.
In a company, someone else pays the salary. Someone else decides strategy. Someone else takes the final blame. In a startup, all of that lands on you. I’d never seen how either of us would handle no salary, no boss and no one to escalate to. You can’t test that in advance. You can only talk about it openly and agree on what you’ll do when it gets hard.
So we talked about it. A lot.
The conversations to have before you start
Before saying yes, I think every pair of co-founders should have a few uncomfortable conversations. Not because the answers must match perfectly, but because you should know where they differ before it matters.
1. What do we each want from this? Do you want to build something huge, or a healthy business that pays you well? Would you sell in three years if someone offered, or never? Do you want to raise money? (I wrote a whole essay on investors versus independence, and this is where that question starts.) If one founder wants a rocket and the other wants a calm, profitable company, that’s a fight waiting to happen.
2. How much can each of us risk? How long can each person go without a salary? Who has family depending on them, a loan, a partner with opinions? These aren’t rude questions. They decide how long the company can survive and how much pressure each founder will feel.
3. How much will we work? “As much as it takes” is not an answer. Are we both full-time? Weekends? What if one person wants to slow down after a year? Unequal effort is one of the most common reasons co-founders fall out, and it usually starts with vague expectations.
4. Who decides what? More on this below. It’s the conversation people skip most often, and regret most.
5. What happens if one of us wants to leave? Nobody wants to talk about the breakup on the first date. But in a company, you have to. What happens to their shares? Who keeps the code, the domain, the customers? It’s far easier to agree on this while you still like each other.
Put it in writing
The most important advice I’ve ever received about business, from my first business teacher William Skelley, is to read every word you sign. The flip side of that is just as important: sign things. Don’t run a company on a handshake, even with your best friend.
A co-founder agreement doesn’t have to be long. It should cover at least:
Equity: who owns what. There’s no single correct split. Many founders who start together with similar commitment choose an equal or near-equal split, because a big difference can create resentment for years. Others weigh who had the idea, who’s full-time, who brings money. Whatever you choose, choose it openly and write down why.
Vesting. This is the protection people understand least and need most. Vesting means founders earn their shares over time, often over four years, with nothing earned in the first year (the “cliff”). If someone leaves after six months, they don’t walk away with half the company they stopped working on. It protects everyone, including the person who leaves, because it makes the rules clear in advance. I explained vesting in more detail in Read Every Word You Sign.
Roles and titles. Who is CEO? Who is responsible for product, for engineering, for sales?
Ownership of work. Everything built for the company belongs to the company, not to whoever wrote it.
Leaving. What happens to shares, responsibilities and access if someone leaves, by choice or not.
Big decisions. Which decisions need both founders to agree: raising money, selling the company, hiring a key person, taking on debt.
Writing this down doesn’t mean you expect things to go wrong. It means you respect each other enough to be clear. And if you can’t agree on the paper, you’ve just learned something very important, cheaply.
Get a lawyer to review it. It costs money. It costs far less than a fight later.
Splitting the work
“We’ll decide everything together” sounds friendly and is a trap. Two people deciding everything together means every decision takes twice as long and every disagreement becomes a standoff.
What works better is clear ownership. Each founder owns certain areas and has the final word there, after listening to the other.
At Santara, my main areas are product direction and the technical side: the backend architecture and the AI pipeline that turns messy messages into the morning briefing. That doesn’t mean my co-founder has no opinion on the product. It means that when we can’t agree on a product question, someone has to decide, and we already know who.
A few rules that help:
- Disagree openly, decide clearly, then commit. Once a decision is made, both founders support it fully, even the one who lost the argument. No “I told you so” later.
- Don’t split the same job in half. Two people half-owning sales means nobody owns sales.
- Review the split every few months. The company changes. What made sense with zero customers may not make sense with fifty.
- Have a tie-breaker. For decisions that truly affect the whole company, know in advance how you’ll break a tie. Sometimes it’s the CEO. Sometimes it’s an adviser you both trust. At Santara, having William as an adviser helps: not to decide for us, but to help us see a problem from outside.
HiTaVa: building with my girlfriend
Starting a business with a partner you love is a different kind of risk. Everyone has an opinion about it, and most of those opinions are warnings.
The warnings aren’t wrong. When work and relationship are tied together, a bad week at work can follow you home. An argument about money can become an argument about everything. And if the business fails, or the relationship does, the other one gets hurt too.
So why do it? Because it works for us, and here’s what I think makes it work.
She runs it. This is the most important part. HiTaVa is a two-person business, and my girlfriend runs almost everything day to day: the templates, the customers and the sales. I help with product direction and the technical side. There’s no question about whose business it is in practice. That clarity removes a lot of possible conflict.
Clear lanes. We don’t both try to do everything. Because the lanes are clear, I don’t second-guess decisions in her area, and she doesn’t have to wait for me to approve them.
The business is small on purpose. HiTaVa sells ready-made spreadsheet templates to small businesses. It’s a boring business in the best sense. It doesn’t need us to bet our savings or work through every night. Lower stakes mean less pressure on the relationship.
Work talk has limits. This is the hardest one for two people who both think about work too much. Not every dinner should be a planning meeting.
The same rules still apply. Being a couple doesn’t replace clear agreements. If anything, it makes them more important. It’s much easier to agree on how you’ll handle things while everything is good.
I wouldn’t tell everyone to start a business with their partner. But I don’t think it’s automatically a bad idea either. It depends on the business, the people and, most of all, how clearly you divide the work.
Red flags I’d watch for
Whoever you’re thinking of building with, these are the warning signs I’d take seriously:
- They want the title more than the work. If they care more about being “CEO” than about who does what, be careful.
- They avoid the money conversation. Founders who won’t talk openly about equity, salary and risk at the start won’t get easier later.
- They never admit mistakes. You’ll both make many. If one of you can’t say “I was wrong,” the company will pay for it.
- They don’t follow through on small things. If they miss deadlines when the stakes are low, they’ll miss them when the stakes are high.
- You feel relieved when they’re not around. Trust that feeling. A startup will multiply it.
- They want something very different from you, and neither of you will say it out loud.
And one green flag that matters more than any skill: you’ve seen them at their worst, and you still want to work with them.
A short checklist
If you’re about to say yes to a co-founder, ask yourself:
- Have I worked with this person on something hard before?
- Have I seen how they handle pressure, failure and disagreement?
- Do we want the same kind of company, at the same speed?
- Have we talked honestly about money, risk and how much we’ll work?
- Do we know who owns which decisions?
- Have we agreed on equity and vesting, in writing, reviewed by a lawyer?
- Do we know what happens if one of us leaves?
- Would I still choose them on a very bad day?
If you can answer yes to most of these, you’re starting from a strong place. If you can’t, that doesn’t mean “don’t.” It means “talk more first.”
The person matters more than the plan
I’ve come to believe that choosing a co-founder is the most important decision a founder makes. More important than the idea, which will change. More important than the first product, which will be rebuilt. Maybe more important than the money.
Ideas can be fixed. Products can be rewritten. A broken partnership almost always breaks the company with it.
So take your time. Work together on something small first if you can. Have the uncomfortable conversations. Write things down. And choose someone you trust on the bad days, because in a startup, there will be plenty of them.
Related: Nothing Was Wrong. That Was the Problem., on why I left a good job to start Santara, and Read Every Word You Sign, which explains vesting and other terms in plain language.
