In vitro transcription (IVT) device utilizing a hollow-fiber bioreactor for RNA synthesis; Continuous flow IVT device for RNA production and purification; Modular IVT device for production and purification of conventional mRNA and self-amplifying RNA; Modular IVT device for encapsulating purified conventional mRNA and self-amplifying RNA in a lipid nano-particle (LNP); Self-contained modular inserts containing enzymes and chemicals for in vitro transcription and purification of RNA; Self-contained modular inserts for producing and for encapsulating RNA in LNPs; Self-contained modular inserts containing enzymes and chemicals for isothermal amplification of RNA; Reagent kits including enzymes and chemicals for in vitro transcription of RNA; Reagent kits including enzymes and chemicals for purification of RNA; Reagent kits including chemicals and reagents for encapsulating RNA in LNPs; Reagent kits including enzymes and chemicals for isothermal amplification of RNA