An important technical distinction regarding the collection of paradata in web surveys is that they can be collected on the server side and/or the client side. In web surveys, paradata is categorized into device-type paradata and questionnaire navigation paradata. Device-type paradata provide information regarding the kind of device used to complete the survey. Questionnaire navigation paradata describe the entire process of filling out the questionnaire. This chapter provides examples of usage for device-type and questionnaire navigation paradata. Another use of paradata pioneered in the early 2000s by Jeavons is adaptive scripting. Adaptive scripting refers to using paradata in real time to change the survey experience for the respondent. The chapter also discusses two main classes of software to collect paradata such as specific paradata software and paradata collection tools embedded in commercial and non-commercial survey platforms. Ethical and communication issues are important considerations in using web survey paradata.