The digital collections of the St. Louis Mercantile Library span several generations of technology. In the process of keeping up with best practices in digital access and preservation, and in meeting the needs and requests of students and researchers, many artifacts and documents have been digitized to a variety of standards over the years.

Currently the library is particpating in two platforms hosted by the University of Missouri system. The UMSL Digital Library was built by Mercantile staff and is the primary focus of current digital projects. Items related to the history of the Mercantile may be found in the UM system's institutional repository, MOspace.

Because migrating to new platforms requires long systematic effort, there are still many other items to be found online from previous intitiatives in partnership with other institutions. There are several books available electronically.  Some content may also be found on the University of Missouri's old Digital Library and on the Missouri State Library's Missouri Digital Heritage. Missouri Digital Heritage is especially important because it holds select backups of the Mercantile's content along with materials from other libraries around the state of Missouri. Partnering with the Missouri State Library has provided an important source of funding for the Mercantile's digital initiatives.

Digital content, especially finding aids, can also often be found as PDFs or galleries on the collection pages accessed from the special collections directories on this site. Some collections may also have special databases associated with them only accessible from the individual collection page.

In addition to the various digital collections and galleries, there the library also hosts several online exhibits.