Prevent duplicate submissions

Turn on Prevent duplicate submissions in a form’s Settings to accept one response per respondent. A second attempt isn’t saved. On a Hosted form the person sees “Response already recorded”. Only responses received after you turn it on are counted. Under Identify respondents by, choose how SurveyOwl recognizes the same person:

Option	How it works	Weak spot
Respondent ID	A random ID kept in the browser.	Another browser, another device or a private window gets around it.
IP address	One response per IP address.	Everyone sharing a network, like an office or a school, is blocked after the first response.
Form field	One response per value of an answer, such as an email address.	People can type a fake value. Pair it with email verification if that matters.

For Form field on a Hosted form, pick the question that identifies people. It has to be a Short Text, Email, Phone Number, Website or Number question. Choice questions can’t be used, because many people pick the same option.

Endpoint forms

On an Endpoint form there are no questions to pick from, so for Form field you type the field’s name, for example email, exactly as it appears in your submission. For Respondent ID, your code has to send a UUID in an X-Respondent-Id header. Submissions without the header are still accepted. That makes this option easy to bypass, so IP address or Form field is usually a better fit for Endpoint forms. A rejected duplicate comes back with the error code duplicate_submission. Show your visitor a friendly message when you see it.

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Prevent duplicate submissions

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