Find a co-founder. Then find out if it works.
Meeting someone is the easy part. Cofounnder is where you meet founders and then actually test the partnership, through alignment checks, real questions, an equity split and signed agreements, before anyone commits a year of their life.
Free on iPhone and Android. English and Lietuvių.
The problem
Most co-founder break-ups were predictable
The idea rarely kills a startup. The partnership does. Yet founders evaluate a potential co-founder with far less rigour than they'd apply to a single engineering hire.
65%
of high-potential startups are estimated to fail because of co-founder conflict, not the product.
Months
of equity, time, and momentum are on the line before most founders ever stress-test the relationship.
Gut feel
is still how most pairs decide, a few coffees, shared excitement, and a handshake.
The exact numbers vary by study, but every founder who’s lived through it tells the same story.
How it works
From a stranger to a signed agreement
Most co-founder tools stop at the introduction. Cofounnder covers the whole distance, from finding someone to writing down what you agreed, in one place and in the order it actually happens.
- STEP 01
Say what you are building
A short profile: what you are working on, what you bring, and what you need someone else to bring. If the idea is still vague, the Idea Lab helps you get it down to one sentence first.
- STEP 02
Meet founders
One profile at a time, or as a list and a map if you would rather search. Every profile carries a fit score based on what each of you brings and needs, so the ones worth reading come first.
- STEP 03
Connect, then talk
Interest stays private unless it is mutual, so there is no cost to being interested and nobody gets unsolicited messages. When you both say yes, the conversation opens.
- STEP 04
Test the partnership
This is the part most founders skip. Work through alignment, interviews, equity and agreements together, at whatever depth the relationship has earned.
What you keep
A written record
An equity split in plain English, a signed NDA, a partnership agreement you both hold. Not screenshots of a chat, and not something one of you can quietly rewrite later.
What it costs to stop
Nothing
Every step is something you can walk away from. That is the point of doing them early, while walking away is still cheap and nobody has moved house or turned down a job.
What's inside
Six ways to find out before you commit
Each one is a room you can walk into with someone, or on your own. Take them in order or take the one you need. Nothing is compulsory and nothing costs anything.
Idea Lab
Not sure what to build yet? Shape it on your own first.
Looking for a co-founder before you can say what you are doing is the hard way round. Answer a short set of questions, work through sprints, and come out with a brief you can put in front of anyone.
Half an hour to start · on your own
Alignment
Find out whether you actually agree, before it costs you.
Most partnerships do not fail on skills. They fail because two people wanted different things and nobody asked. You each answer the same questions alone, then see both sets side by side.
About 15 minutes each · with a partner
Interview
Ask the hard questions while it is still easy to walk away.
A real interview: you ask, they answer, you read. Written rather than spoken, so nobody has to think of the perfect follow-up on the spot and nobody can talk their way past a question.
10 minutes to send · with a partner
Equity & terms
Agree the split, in plain words, before you build.
Four questions each, no jargon and nothing to type. You get a starting number and, more usefully, a clear view of anything the two of you see differently.
About 5 minutes each · with a partner
NDA & Agreements
Put it in writing, before and after you commit.
A mutual NDA for the early conversations and a partnership agreement for after you decide. Both fill themselves in from what you already agreed, and you sign with your finger.
10 minutes for an NDA · with a partner
Startup toolkit
Set the company up properly, one step at a time.
The paperwork nobody explains: what to register, in what order, and why. Fillable drafts, equity and runway calculators, and somewhere to keep the documents once you have them.
Go at your own pace · on your own
Why it's different
Built for the decision, not the dopamine
Cofounnder is not trying to keep you scrolling. It is trying to get you to a good decision about one specific person, and then out of the app.
Matched on what you need
A fit score built from what each of you brings and what each of you is missing, so it favours people who complement you rather than people who look like you.
Interest stays private
Nobody is told you were interested unless they are interested back. There is no cost to saying yes, and no way to be rejected in public.
No unsolicited messages
You cannot message someone who has not accepted a connection. There is no public feed and no way to broadcast at strangers, which removes most of what makes networking apps unpleasant.
Verified profiles
Every photo passes automated review before anyone sees it, and founders can verify their identity with a government ID or a liveness check to earn a badge.
Documents you both hold
NDAs, partnership agreements and equity summaries generated from what you agreed, signed in the app, and exportable as PDFs that live outside it too.
English and Lietuvių
The entire app, not just the menus, in both languages. Founders shouldn't have to negotiate equity in their second language if they'd rather not.
FAQ
Questions, answered
How much does it cost?
Cofounnder is free. Every part of it, including the equity tools, the agreements and the toolkit. There is no subscription, no trial and nothing behind a paywall. Founders are usually tightest on money at exactly the moment this decision matters most, so charging you to get it right would be a strange way to help.
Is this a dating app for co-founders?
It starts the same way, because meeting people has to start somewhere, and it is deliberately quieter than that: interest stays private unless it is mutual, nobody can message you without an accepted connection, and there is no public feed. What happens after the introduction is the actual product.
Do we both need it?
For finding someone, yes, they need an account. After that it depends. Idea Lab and the startup toolkit are solo. Alignment, interviews, equity and agreements are two-sided by design, because a one-sided answer to "do we want the same thing" is not worth much.
Do I need an idea already?
No. Plenty of people arrive with skills and no idea, or an idea they cannot yet explain. Idea Lab exists for exactly that: it turns something vague into a brief you can put in front of someone, before you go looking for a partner.
Are the agreements legally binding?
The NDA and partnership agreement are real documents you both sign, and you keep a copy. They are a solid, plain-English starting point, not a substitute for a lawyer, and we say so in the app. For anything that matters, take the summary Cofounnder produces to a solicitor. That is what it is designed for.
Does it use AI?
In places, and not for the decisions. It drafts interview questions you then edit, helps shape an idea in Idea Lab, and screens photos and profile text for safety. It does not decide whether to match you with someone or whether a partnership is a good one. We name our AI provider in the Privacy Policy, and your inputs are never sold.
Who is it for?
Adults (18+) seriously considering a startup partnership, first-time and repeat founders alike. It is available in English and Lithuanian.
How do you keep it safe?
Every profile photo passes automated review before anyone sees it, and profile text is screened too. Founders can verify their identity with a government ID or a liveness check. Report and Block are on every profile and every conversation, and reports reach us directly.
Don’t bet years on a hunch
The right co-founder can make a startup. The wrong one can end it. Find out which one you have while finding out is still cheap.
Free on iPhone and Android. No subscription, nothing paywalled.