Connexions, later known as OpenStax CNX[1] was a global repository of educational content provided by volunteers.

[2] Founded in 1999 by Richard Baraniuk, Connexions was based on the philosophy that scholarly and educational content can and should be shared, re-used and recombined, interconnected and continually enriched.

As such, it was one of the first Open Educational Resources (OER) initiatives along with projects such as MIT OpenCourseWare and the Public Library of Science.

The materials in Connexions are available under a CC BY Creative Commons license, which means that content can be used, adapted, and remixed, as long as attribution is provided.

[4] Connexions contained educational materials at all levels—from children to college students to professionals—organized in small modules (pages) that can be connected into larger collections (books).