Public survey links are bearer links: anyone who receives a valid link may be able to open the survey until the link expires, is revoked, or is used up.
When to use a public link
Use a public link when your protocol allows open recruitment or anonymous response collection. Use invitation codes instead when only selected participants should join or when you need stronger control over who can access the study.
Sharing rules
Share links only in the channels approved for the study.
Do not put participant names, email addresses, or health details in the link or surrounding message.
Treat single-use links as private to one intended respondent.
Treat multi-use links as public once they leave your controlled channel.
Error behavior
Invalid, expired, revoked, or already-used links should not reveal detailed project or participant information. A generic error protects participants and prevents code guessing.