The purpose of this work is to design and create the server part of the application. That is, creating the Application Programming Interface (API) which will return all the necessary data to the client part of the application for display purposes. The API is divided into four categories of endpoints. Administrative endpoints that allow retrieving configuration data that is required on the client side of the application. Endpoints for users that manage the creation of user data, updating data and retrieving user data. Endpoints for establishments that enable the creation and deletion of establishments and the retrieval of their data, there is also the possibility of retrieving data by certain parameters such as the owner of the establishment and by searching by the name of the establishment. Reservation endpoints that are used for creating a new reservation, changing the status of a reservation, retrieving reservations by certain parameters such as the owner of the establishment for which the reservation was created and by the user who requested the reservation. These endpoints are also the ones that send notifications about new reservations to the establishment’s owner, when reservation status changes they notify the user, and they also create a QR code if a reservation has been accepted that contains information about the reservation. The technologies used in creating the API are JavaScript, Node.js, Express, Firebase-admin sdk. Firestore Database was used for storing the data, and Firebase Storage was used for saving images. Access to the API is secured with JSON Web Tokens (JWT).