The precise point positioning (PPP) method is a relatively young method of GNSS observations processing but it is already quite widespread in many cases. However, the processing of observations with this method using specialized software requires some experience and competencies. The advent of web services for processing the results of observations using the PPP method significantly simplified this task. This circumstance is especially important for workers in the cadastral sphere, and makes it possible to simplify their work in determining the coordinates of points. In the article the possibility of using a web service for online processing of the results of GNSS observations CSRS-PPP for geodetic support of cadastral works is researching. The research includes several stages. At the first stage, the general stability of the results which obtained by GNSS observations processing with this service is estimated. For this, we compare the results of processing GNSS observations using CSRS-PPP for several cycles of daily observations with the results of processing these observations using the classical double difference relative method using commercial software. The results showed a high level of convergence of the obtained solutions, which indicates the stability of the web service CSRS-PPP. At the second stage, the convergence of the results obtained by processing short observation time intervals is evaluated. For processing, time intervals of 1, 2, and 3 hours were selected, because such time intervals are most often used for geodetic support of cadastral works. The estimation results in comparison with the results of daily observations by the double difference method, is adopted here as a reference, also showed a high convergence of the observation results. The convergence of determining the position of single points based on the results of short time interval observation sessions was evaluated in comparison with the result of processing daily observations. The results show a significant increase in the convergence of the obtained results with an increase in the duration of the observation session on the basis of which and also on results of total estimation of research the conclusions and recommendations on the use of the web-service CSRS-PPP for geodetic support of cadastral works are made.