As part of the small team in this start-up I work on the client side of the single-page application using React.js with Redux, this front-end work consists of building many new application components from scratch, creating them based on the design specifications in the wire-frames provided as well as configuring/fixing existing ones.
I also work on our server side micro-services, adding new features to our back-end (eg. user authentication, importing and exporting information from the web app to our database and vice versa, integration of 3rd party API's (payment, accounting, etc..) in our application).
Lastly Unit/integration testing on both front-end and back-end components (Mocha, Chai, Ava).