If these are the only requirements (e.g you don’t need many ethernet ports or WiFI), I would suggest you consider the following models, as they meet your listed requirements:
Routers: RUT200, RUT241
Gateways: TRB140
All Teltonika Networks routers and gateways have the RutOS operating system and supports Web APIs. For information on using APIs with our products, please visit the following page, where you’ll find tutorials, examples, and other related resources: