Frappe has OAuth2 Provider - Although ERPNext (app) is monolithic, any device which can become OAuth2 client can communicate with Frappe (framework) seamlessly. OAuth2 enables microservices ( OAuth and OpenID Connect for Microservices - YouTube )
I think philosophy is a little different. I’m not a user of Tryton but I regularly have a look. Tryton comes from TinyERP I guess (old version of Odoo/OpenERP) and the technically, the framework can have some similarities.
Tryton is quite quality-focused, with many tests for example. The Web UI is near of a copy of the desktop / GTK client and ergonomics are de facto similar.
Tryton seems to be dedicated to pure ERP / internal management whereas Frappé and ERPNext include website, portal, ecommerce… Frappé also enables many graphical customizations, without advanced technical skills.
About support and versioning : ERPNext is SaaS like with rolling type release. Tryton has stables versions every few months (6 ?).
About contribution : it seems that Frappé+ERPNext has more contributors and activity than Tryton.
Lastly, each solution is really open source (100% of the source + upgrades) and built on top of Python.
This is interesting. Maybe some day we could have details on how to do simulation for reorder and safety stock. And hopefully also get it integrated into ERPNext - is that possible @Not_a_countant?