We've released 2 additional options for custom variables adding further flexibility to your survey configuration. Now available on Enterprise Plans and above.
Custom variable required
This option will make the survey variable required in order for the survey link to work. Having an empty value will throw a "Survey Link Invalid" message.
Custom variable unique
This option will make the survey variable value unique within the database. As soon as a response has been completed with a certain value, no more responses will be allowed with the same value.
Respondents who access the survey with the same value will receive a "You have already completed this survey" message.
- See our updated help guide for Custom Variables for more information