A new report showcases the 20 top-trending open source startups around the world, more than half of which are closely aligned with AI.

The report is the handiwork of European venture capital firm Runa Capital, which has operated the Runa Open Source Startup (ROSS) Index since 2020. The Index serves quarterly updates on the fastest-growing projects in terms of GitHub “stars” — a metric that’s something akin to a “like” on social media. Beginning in 2023, Runa started producing annual reports, highlighting the most popular commercial open source startups in a given year.

Last year’s report demonstrated that AI and data infrastructure were driving demand for open source tooling, with LangChain hitting pole position in the ROSS Index for its open source framework for building LLM-centric apps.

This year it’s a similar story, with AI central to 11 of the top 20 companies.

It’s worth noting that the ROSS Index is heavily curated and doesn’t include any old open source project. Qualifying projects must be closely linked to a commercial company (i.e., a vendor-led project), meaning no side projects. Additionally, these companies must be younger than 10 years old; raised less than $100 million in funding; and be entirely independent — so not a subsidiary or publicly listed.

Stargazing

In top spot on the 2024 ROSS Index is Ollama, a Y Combinator alum that’s built an open source tool for running LLMs such as Meta’s Llama and DeepSeek locally (i.e., desktop). Ollama’s GitHub star count increased by some 76,000 through 2024, growing 261% to more than 105,000 (it has since risen to more than 135,000 stars over the past few months).

Next on the list is Zed Industries, a cross-platform collaborative code editor “designed for high-performance collaboration with humans and AI.” The Zed project has been around for a while, but it only went open source in January 2024, and through the rest of the year it gained more than 52,000 GitHub stars.

In third place is LangGenius, the company behind an open source LLM app development platform called Dify. The project attained more than 43,000 new GitHub stars last year, growing 326% from around 13,000 to nearly 57,000 — a figure that has since surged to more than 84,000 stars.

And then there is ComfyUI, an open source node-based program for generating images, videos, and audio using generative AI models. The project’s GitHub star count grew 195% to 61,900 stars last year.

Rounding out the top five is All Hands, the company behind an open source platform called OpenHands for building software development agents. OpenHands garnered 39,600 GitHub stars from its launch last March through the end of 2024 and has since added another 12,000 stars to the mix.

While the ROSS Index for last year illustrates the explosive growth in AI and LLMs, it also shows how developer tooling is still hot in the world of open source, with the likes of Zed and Astral’s UV (No. 9) both featuring in the top 10. Elsewhere, the presence of PDF manipulation tool Stirling PDF (No. 7), finance management software Maybe Finance (No. 8), and remote desktop software RustDesk (No. 17) suggests privacy-focused self-hostable tooling is still in high demand.

And Ethereum blockchain-focused Fuel (No. 12) shows that crypto/web3 is alive and kicking.

Open source software by its very nature has always been distributed, given that contributors from all corners of the globe can get involved. This is often the case for vendor-led projects, too; however, commercial entities usually have some center of gravity — even if it just means where it has been formally incorporated.

The ROSS Index for last year shows that San Francisco is home to six of the top 20 ROSS startups, while Canada has three, and Europe (U.K., Switzerland, Hungary, and Czech Republic), Singapore, and China constituting the rest.

Methodology

There are other ways of tracking “hot” open source projects. Two Sigma Ventures operates the Open Source Index, which is similar in concept to the ROSS Index except it showcases the top 100 projects without a specific focus on commercial startups (it also offers different ways of filtering the data).

And GitHub itself offers a top-trending project list, again without the specific focus on commercial businesses.

It’s also worth looking at the methodology behind the ROSS Index. GitHub “stars” can be an imperfect metric, as it merely shows that someone has “liked” the project, as opposed to actively using or monitoring it. Older projects will naturally have procured more “stars,” too, which is why Runa focuses on the relative growth of repositories over a 90-day period for its quarterly reports, and on the absolute number of new stars gained during the year for its annual report.

This also means that the annual report can look quite different to the quarterly reports, given that absolute star counts won’t always align with rapid relative-growth patterns.

There may also be some issues around what is classed as “open source.” While many of the projects on the list have indeed been released under a recognized copyleft or permissive open source license, this isn’t a strict stipulation of the ROSS Index. Runa says it adheres to the “commercial perception” of open source, rather than the official open source definition. As such, a company that has released its software under the Server Side Public License (SSPL), for instance, would still qualify as open source, even though the Open Source Initiative has not rubberstamped the SSPL as “open source.”

Still, the Index is a useful indicator not only of what kinds of open source technology is trending, but also what companies are trying to build businesses atop them.