The article discusses the problem of validation and quality control of data obtained from an online survey. Shown is the role played by various indicators related to the category of paradata in solving this problem. The classification of the paradata on three grounds is proposed: the stage of research, the method of fixation, software. Typical cases of using paradata to assess the quality of online survey data are analyzed using specific examples. In conclusion, the conditions necessary for the standardization and universalization of the process of quality control of online survey data through paradata are formulated.