For several years Facebook released React and a cluster of related projects under a “BSD + Patents” license: the permissive three-clause BSD license paired with a separate PATENTS file granting a patent license. The catch was in that PATENTS file. Its patent grant was conditional and contained a retaliation clause, so that anyone who brought a patent claim against Facebook, even unrelated to React, could lose their patent license to the software. To Facebook this was a defensive measure against patent litigation; to many users it was an unacceptable string attached to what was otherwise presented as open source.
The conflict came to a head in 2017. On July 15, the Apache Software Foundation’s vice-president of legal affairs placed the Facebook BSD+Patents license into “Category X” on the foundation’s third-party license policy page, meaning Apache projects could not include or depend on software under that license. The foundation’s reasoning was that the patent-retaliation terms shifted risk onto downstream users in a way that violated its policy of being a “universal donor,” and that the terms could not be sublicensed under the Apache License version 2.0. Several Apache projects that depended on Facebook libraries, including those using RocksDB, were given a short window to resolve the conflict.
The Apache ruling turned a simmering complaint into a crisis of confidence. High-profile open source projects, most visibly WordPress, announced they would move away from React rather than accept the patent terms, and the broader JavaScript community debated whether React could still be considered safely open. The pressure was substantial because React sat at the foundation of a large ecosystem of web tooling, and uncertainty about its license threatened that whole dependency graph.
Facebook reversed course. On September 22, 2017, engineering director Adam Wolff published an announcement on the Facebook engineering blog stating that the company would relicense React, Jest, Flow, and Immutable.js under the plain MIT license. Wolff wrote that React was “the foundation of a broad ecosystem of open source software for the web, and we don’t want to hold back forward progress for nontechnical reasons.” He acknowledged that while Facebook still believed its BSD+Patents license offered some benefits, the company had “failed to decisively convince this community,” and the relicensing shipped with the release of React 16.
The episode is a landmark in open source governance. It showed that a single dominant project could not impose unusual patent terms on a community that had alternatives, and it demonstrated the practical power of a standards body like the Apache Software Foundation to enforce a coherent licensing policy. The plain MIT license that React carries today is a direct outcome of that pressure, and the affair is frequently cited as a case study in how license choice and community trust are inseparable.