How to find a cofounder

Start with people you have worked with, then widen the search: Y Combinator's free Co-Founder Matching, founder meetups, and the people who reply when you post what you are building. Work on something together for a few weeks before anyone talks equity. Expect to meet a lot of people first.

Do you need a cofounder at all?

Fewer founders think so. Carta's data shows over a third of new companies in the first half of 2025 had one founder, against under a quarter in 2019. Round sizes and valuations were comparable from priced seed to Series B. The numbers come from a December 2025 report by a programme that backs solo founders.

What do investors think of solo founders?

Views differ. Ann Miura-Ko of Floodgate says in the same report that about one in eight or one in ten companies in her own deal flow has a solo founder. Charles Hudson of Precursor Ventures says his first choice is two closely matched cofounders, with a strong solo founder second.

Show the work before you ask. Engineers judge a founder by what is already done: customer conversations, a waitlist, a rough prototype, a first payment. Look where engineers who want to start companies gather, such as YC's matching, where London has nearly as many active profiles as San Francisco.

Should you hire a founding engineer instead?

Many solo founders do. Carta's data shows engineering is the most common first hire for solo and team-founded companies alike. One solo founder in the report met 55 people before offering the founding engineer role, and an investor quoted there says solo founders often offer too little equity to win the best engineers.

Work together before you decide. A trial project of a few weeks shows how you disagree, how fast each of you moves and what each of you wants from the company. YC's platform asks for no commitment and no equity while people get to know each other. Do the same.

What should cofounders agree before they start?

Put five things in writing: who does what, how many hours each of you gives, the equity split with vesting, what happens if one of you leaves, and who breaks a tie. A lawyer can turn that into a founders' agreement. The conversation is the part that matters.

It helps the right people find you. A founder who posts what they are building, what customers said and what skill they are missing gives a future cofounder a reason to write, and a month of posts to judge them by. That beats a cold message to a stranger with a pitch deck.

innernote is the best tool for founders who want to post about what they are building, in their own voice, while they build it.

Say what happened this week in a voice note, and innernote writes the post in your voice. It writes posts ahead, so a busy week still has one ready, and it posts on the days you pick. You read every post first. How founders share the work as it happens is in what is building in public.