He Lost His Co-Founder, Raised $50M Solo, Then Rebuilt It All
Key Takeaways
- "If there's a doubt, there's no doubt." A co-founder is one of the top three most consequential decisions you'll ever make — and your most expensive "employee." The bar should be: I can't imagine doing this without them.
- Don't co-found with someone you haven't worked with — even a ten-year best friend. You don't know how someone works until you've worked with them, ideally through conflict.
- Vesting schedules are broken. A company shows nothing at twelve months. Four-year vesting gives away too much, too soon. Flo argues for six.
- The cure for burnout isn't rest — it's momentum. Energy comes back the moment the work gets exciting again.
- When to kill a company: building has two phases — prospecting for gold (a one-person job) and operating the mine (a full-time job). If you're digging the wrong ground, no amount of digging skill helps.
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Introduction
In 2022, Flo Crivello published an essay called "Co-Founding Considered Harmful." At the time, the prevailing startup advice was unambiguous: don't go it alone, find a co-founder, two is better than one. Flo argued the opposite — that going solo should be the rule and a co-founder the exception. Almost nobody agreed with him. Four years later, almost everybody does.
What makes Flo a compelling voice on this isn't the essay. It's that he wrote it from experience, not theory. He had already lost a co-founder — a best friend of more than ten years. He had already raised roughly $50M as a solo founder, from blue-chip investors like Coatue, Menlo, and Battery. He had already watched the market collapse under his first company, cut two-thirds of a 45-person team, and rebuilt alone into Lindy, one of the most ambitious AI agent startups in the world.
This conversation is the full story behind the essay — and a clear-eyed operating manual for anyone weighing whether to do it alone.
"Co-Founder Breakups Are Startup Dark Matter"
Flo's case against co-founders started with a pattern he couldn't unsee. In San Francisco, he says, "you can't cross the street without running into five founders" — and he watched co-founder breakups destroy company after company up close. The data backed it up: breakups are one of the leading causes of early startup death.
But the public conversation never reflects this, because it can't.
"The public sphere is not representative of reality, because there's a whole category of stuff — the more negative stuff — that you're simply not allowed to talk about publicly."
Breakups are everywhere and invisible at the same time. Talk about yours honestly and you'll get sued. So the advice stays cheerfully pro-co-founder while the reality stays hidden. That gap is exactly what Flo set out to correct.
The Bar for a Co-Founder: "If There's a Doubt, There's No Doubt"
Flo doesn't argue that co-founders are always wrong. He argues the bar should be extraordinarily high — because the stakes are.
"Your co-founder might be the top three most consequential decisions you make in the history of your company. This is your most expensive employee — you're giving away half your company."
His test is simple and demanding: you should be over the moon. I can't imagine doing this without them. Anything short of that is a no. And because a co-founder breakup is a "tail event" — rare but potentially fatal — you have to evaluate for the catastrophe, not the smooth stretches:
"If a car drives fine for 500,000 miles but at some point explodes and kills you, that's not a good car. You don't judge it by how well it drives — you judge it by whether it's going to kill you."
The practical signals? Don't co-found with someone you haven't actually worked with, ideally through conflict. Watch how they describe past disputes — can they characterize the other side charitably, or is everyone else always the problem? And fix the incentives: Flo thinks standard four-year vesting hands over too much equity before a company has shown any signs of life, and would stretch it to six.
From Uber to an Accidental Company
Flo's own path to solo founding wasn't a plan. After almost five years at Uber, he left post-IPO intending to travel for a year. A month in, Covid hit, and he found himself stuck at home building a virtual office for remote teams — Teamflow — almost by accident. The company's legal entity is still named "Gulp," a relic of the day a friend with a three-day window to reinvest an exit called him up: "I have a million bucks — it's probably your company."
"Six hours later I had a bank account and a legal entity. God bless America — this would've taken three weeks in France."
The co-founder he later took on came from that same casual, hacking-with-a-buddy energy — and that, Flo says, was the mistake. They'd been friends for a decade but had never worked together. Within a few months the intensity mismatch was obvious, and they parted ways. The legal aftermath was brutal. But going solo, for Flo, was a relief: "I have hermit tendencies. People hate building alone — I love it. I can move as fast as I want."
When the Market Moves On — and How Deep to Cut
Teamflow rode the remote-work wave up. Then everyone went back to the office, and the same growth charts ran in reverse. Nothing moved the needle. This, Flo says, is the hardest place to be: a persistent founder when things are genuinely hard.
The turning point was GPT-3. Flo had been watching AI since GPT-2, and as his team bolted language models onto the product — first summarizing meetings, then updating any field in any CRM — it clicked: agents, before anyone was using the word. The pivot to Lindy meant cutting the team from 45 to a handful.
"We went from 45 people to 15 — and that was still too big."
His lesson: cut deeper than feels comfortable. The ideal 0-to-1 team is three to five builders. He frames it with Elad Gil and Naval Ravikant's image of surveying an infinite jungle from a helicopter — you land, clear the brush, and if there's no gold, you climb back in and move on. "The thing is, only so many people fit in the helicopter."
Momentum, the Brain Trust, and the Real Job of a Leader
After two years of what he calls "chewing glass," Flo was convinced he needed six months off before he could pivot. Instead he committed — and his energy came back immediately.
"The cure to burnout is not rest — it's momentum. You don't need as much rest as you think you do. You just need momentum."
He's equally blunt about leadership. The instinct is to be a cheerleader; the actual job is to win, which means naming the ugly truth out loud — we're going to die if we don't solve this. The fear is that people will leave. Some do. "But the people who leave you are probably not the people you want around anyway." The rest are galvanized.
And loneliness — the real bear case for going solo — is solvable. You build a "brain trust": two to four lieutenants you fully open up to, modeled on the way the South Park creators riff in 6 Days to Air or Pixar's no-ego feedback room. Solo doesn't have to mean alone.
The bull case, in Flo's words? "You can move so much faster, and you don't deal with the bullshit."
About Flo Crivello
Florent "Flo" Crivello is the founder and CEO of Lindy, an AI agent platform building the "AI employee" — agents that manage your inbox, calendar, and meetings. A former early Uber engineer and PM, he left after the IPO and accidentally built Teamflow, a virtual office that raised ~$50M (Coatue, Menlo, Battery) before the return-to-office market erased it. He cut the team to a handful and pivoted solo into Lindy as the agent era began. He's also the author of "Co-Founding Considered Harmful" (2022), one of the most-cited contrarian essays in solo-founder circles.
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