Why Permissive Open‑Source Licenses Are Dominating 2019 – Trends & Insights

Open source license usage trends

Open source licenses are often seen by developers as a boring compliance issue, but as open‑source components become business‑critical, their licensing choices are under renewed scrutiny.

Permissive open‑source licenses are on the rise

Data from the WhiteSource database—over 4 million packages and 130 million files across 200+ languages—show that in 2019 the most popular licenses continued to favor permissive options, while copyleft licenses, especially the GPL family, declined.

Permissive licenses such as MIT and Apache 2.0 topped the list, each gaining about 1 % over the previous year. These licenses impose minimal restrictions, allowing free use, modification, and redistribution, even in proprietary derivatives, with little or no obligation to return changes.

In 2019, 67 % of open‑source components used permissive licenses, up from 64 % the year before. Among the top ten licenses, 33 % were copyleft, down from 36 % in 2018 and 59 % in 2012, indicating a clear developer and organization preference for permissive terms.

Broad industry support for open source—from Microsoft, Google, and many others—has turned open‑source into mainstream, further encouraging the adoption of permissive licenses.

Conversely, developers are gravitating toward components that require fewer licensing obligations, reducing legal compliance burdens.

MIT license remains top

The MIT license held the leading position with 27 % share, remaining popular on GitHub since 2015. According to GitHub product manager and open‑source lawyer Ben Balter, developers choose MIT because it provides a simple copyright notice and disclaimer, requiring no legal expertise to implement.

MIT allows anyone to do anything with the code as long as they retain the notice, without liability. Notable MIT‑licensed projects include Angular.js, Rails, and .NET Core.

Apache 2.0 continues to dominate

Apache 2.0 replaced GPL 3.0 as the second‑most popular license in 2017 and grew another 1 % in 2019 to reach 23 % share. Its key terms require preservation of copyright and license notices, grant explicit patent rights, and allow redistribution of modified works under different terms.

Apache 2.0 is used by many popular projects such as Kubernetes, Swift, and PDF.js.

GNU GPL licenses slowly decline

GPL v3 fell to third place with a 3 % drop to 13 % share, while GPL v2 held fourth at 10 %. Together the GPL family accounted for 28 % of the top ten licenses, marking a continued decline.

GPL, as a classic copyleft license, requires that any combined work be released under the same license, forcing source disclosure. This has led many enterprises to adopt dual‑licensing strategies to reconcile GPL requirements with commercial needs.

Where are open‑source licenses headed in 2020?

Although some licenses did not make the 2019 top ten, shifts in major projects like MongoDB and Redis show organizations are re‑evaluating licensing to stay competitive while embracing open‑source growth.

Industry voices, such as Ansible creator Michael DeHaan, suggest new licensing models may be needed to sustain community development.

Overall, developers and businesses continue to select open‑source components that enable thriving products, and the ecosystem is working to make open‑source adoption and compliance easier.