Entrepreneurship is trying to start a business with the investment of a certain amount of capital and activities in order to achieve a positive financial result. The primary task of the paper is to determine the success of the feasibility of a business plan based on the concept of intermediation of supply and demand within the tourism sector in the Republic of Croatia via an internet site. Marketing is an essential element of every business, including this one, and marketing activities are listed and in what period in order to achieve recognition in the market and potential brand building. Through the analysis of income and expenses, it is determined whether it is worthwhile to start a business venture. Through market research, we try to answer the questions of what is a personalized service, what is offered in the tourism sector in Croatia, what is the number of tourists and whether the market offers the possibility of entry. The business plan has been developed in such a way that business cooperation is concluded with service providers in the territory of the Republic of Croatia, whose offers will be advertised on the website, and in this way, potential clients will have a wider range of offers that they will be able to analyze by themselves and according to their criteria (price, quality, distance, etc.) and decide on the one that suits them best. The success of the business is based on earnings through the commission that the service provider pays as compensation for bringing in a client. The advantage of this type of business is for both clients and sellers, because clients get everything they want in one place (a wider range of offers and information), and sellers advertises themselves so that new clients come to them via the internet site. The service provider has no downside using the internet site as a means of advertising and intermediation, because the commission is based on bringing the client in, and if there is no client, the sellers are not obliged to pay any type of fees.