Quote: "The syntax is inspired by Clojure's Hiccup and Reagent projects, which themselves were influenced by prior art by Phil Wadler at Edinburgh University, who pioneered this approach in Lisp back in 1999. hdom offers several additional features to these established approaches."
However, Reagent also still relies on React under the hood whereas hdom is completely standalone. Also, hdom has a lot more features in terms of what kind of values are supported within an hiccup tree and additionally, in this latest version (5.0), hdom already has been extended to support non-DOM targets to update. Currently, the only user of this feature is the hdom-canvas package (https://github.com/thi-ng/umbrella/blob/master/packages/hdom...), which allows you to define canvas scene graphs in the same way as the rest of the UI, but those virtual shape elements are translated into canvas draw calls. A WebGL version of this is in early progress. In general, by implementing a certain interface you can support any other target context/data structure.
Ps. I've never used Om so didn't list it as an active influence.