While the typical enterprise startup is lucky to attract a handful of users to help bolster its funding pitch before securing an initial seed investment, GitLab B.V. boasts of having signed up more than 100,000. And the fast-rising GitHub competitor is now announcing the completion of a $1.5 million round from early-stage backers to take its code collaboration service to the next level.

The 12-strong Dutch outfit touts many of the same features as its better-known rival but operates under a vastly different business model that takes much of the credit for the explosive adoption up to this point. It’s a radical expansion of the traditional freemium approach of providing core functionality at no cost and charging for everything else that GitHub practices.

GitLab allows users to maintain an unlimited number of private repositories in service with no cap on the number of collaborators who can contribute code, while an on-premise version is available for free download under an open-source license. That has led to a fairly low conversion rate to the premium edition, but the startup  nonetheless managed to achieve profitability before joining the Y Combinator Winter 2015 program earlier this year.

GitLab has gained even more ground against the competition since then and now counts NASA, CERN, Elon Musk’s Space Exploration Technologies Corporation (better-known as SpaceX) and numerous other big names among its users. The new $1.5 million in seed funding will go towards expanding the startup’s San Francisco sales office to help grow that list.

Although small, the round the participation of several heavy hitters from the Silicon Valley investment community, including  Khosla Ventures, 500 Startups and Crunchfund. Ashton Kutcher’s Sound Ventures and Liquid 2 Ventures, the investment fund of football legend Joe Montana, chipped in as well.

The all-star investor roster is in itself indicative of GitLab’s potential, but the road ahead won’t be entirely smooth. One major obstacle that the startup will have to overcome is scaling its current business model, which may prove difficult as the cost of supporting the free users on its cloud service rises with adoption. Meanwhile, GitHub is ramping up its competitive efforts in the background, but the Dutch startup is continuing apace on its aggressive growth trajectory.

Photo via Yuri Samoilov