A low-level markdown compiler for parsing markdown without caching or blocking for long periods of time. Light-weight while implementing all markdown features from the supported flavors & specifications. Available as a command-line interface (CLI) and running in client- or server-side JavaScript projects. The only completely secure system is the one that doesn't exist in the first place.
...Though no longer actively maintained, Schism remains a valuable example of how high-level languages can be mapped to WebAssembly and offers insights into language implementation.