This week, we’re back with another installment in our Paths to Product-Market Fit series, this time with Linear CEO and co-founder Karri Saarinen.
Linear’s Path to Product-Market Fit — Quality and Craft > Speed and Scale

The metrics founders use to measure product-market fit — sales conversion rate, burn multiple, ARR — didn't matter to Karri Saarinen.
He's prioritized a non-numerical KPI since day one of building Linear: quality. Finnish by birth and a product designer by trade, he’s long balked at Silicon Valley’s obsession with scale and speed, which, he thinks, often comes at the expense of craft.
While a design lead at Coinbase and Airbnb, he grew frustrated with the product and engineering team’s project management software. “When I first started using it, I thought, ‘Why is it so messy and complicated?’” he says.
His Finnish friends Jori Lallo and Tuomas Artman, engineers at Coinbase and Uber, used the same tool at their jobs and shared Saarinen’s frustration. Over beers one night, the trio decided to team up to build a better one, figuring there must be a market of IC product builders just like them craving a faster and more elegant tool.
But before rushing to start a company, they let the idea simmer for a while, even running some lightweight user research with coworkers while still at their day jobs.
“Sometimes it's good to not build immediately. We didn’t want to commit right away and move really fast. We wanted to take some time to talk to people and form our thinking around this idea,” says Saarinen.
So when they set out to build the prototype over a year later, Saarinen says this incubation period made the actual work of designing the product very intuitive. ”Because we did so much pre-work and pre-thinking, a lot of the architecture was basically built into the product by the time we started,” he says.
Fast forward to today, and Linear now has plenty of numbers to show for it. Earlier this summer, Linear announced an $82M Series C, bringing its valuation to $1.25B, with a 15,000+ customer roster that includes the likes of OpenAI, Ramp and Vercel.

On The Review, Saarinen walks us through Linear’s methodical six-year build, detailing how the founding team…
- Built a highly opinionated prototype that met the co-founders’ high standards
- Launched in private beta and handpicked early users to join
- Stayed focused on the day-one ICP of IC product builders even with subsequent product launches
- Designed the sales process to be an extension of the product
Saarinen credits Linear’s success with this craft-first ethos, which hasn’t wavered even at its size today. “Quality is our first principle. Every other metric and decision flows from that,” he says.
Thanks, as always, for reading and sharing!
-The Review Editors