No, there is no public API at the moment. We’ve talked about adding public trainer submissions in the past but decided it isn’t something we are interested in doing at the moment. It is a logistical nightmare and would require a major redesign of some of our systems. At the moment there are other projects that are higher priority. So yes, you might see it in the future but we would have no way to give you an ETA.
Making trainers for WeMod isn’t necessarily harder than making cheat tables as long as you understand AOBs and x86 ASM. It also helps if you have a basic understanding of the 3 or 4 big game engines, compilation methods, and some knowledge of low-level languages.