You can enable a toggle in your form settings to ensure each respondent submits your form only once. This helps prevent duplicate submissions, resulting in more accurate and reliable data.
Preventing duplicate submissions is a free feature available to all Tally users.
How it worksAn exampleSelect a form field to prevent duplicate submissionsIP AddressRespondent IDForm fieldsFAQ
How it works
After publishing your form, turn on the
Prevent duplicate submissions toggle in your form settings
. The setting is in the Access section.Select a unique identifier field (such as IP address, email, Respondent ID or any other form field), which Tally will use to detect and prevent duplicate submissions.
Whenever Tally detects a duplicate submission attempt, the respondent will see this error page pop up, preventing them from submitting the form.
An example
You have a registration form with an email input field, and you select it as the unique identifier.
The error page will pop up when someone tries to submit the form again using the same email. The error message uses Tally default form text, which means if you change form language, it will also apply to the error message.
Select a form field to prevent duplicate submissions
You can use any form field as the unique identifier, such as an input field, hidden field, calculated field, IP address, and Respondent ID. You’ll see all available fields for your form when you click the dropdown. Not all options are 100% bulletproof, but each helps deter spam in its own way.
IP Address
An IP address is a unique string of numbers that identifies each computer on the Internet. It functions as an address that allows data to be sent and received between devices on a network.
People in the same company or school often have the same IP address when connected to the same internal network because organizations usually use a shared public IP address for all devices connected to their network. In such a situation, using an IP address to prevent duplicate submissions would restrict other respondents on the same network from filling in your form.
Respondents can avoid being detected by using different networks. For example, they can switch from home Wi-Fi to mobile data or use a VPN, which changes their IP address.
Respondent ID
The Respondent ID is a Universally Unique Identifier (UUID v4), a string of random numbers automatically assigned to every new respondent. It doesn't contain information other than a random string of numbers. The Respondent ID is stored on the respondent's browser (local storage), and if they submit another response, Tally can block it.
Respondents can bypass this check using a different browser or device (e.g., desktop vs. phone), or Incognito mode.
Form fields
You can pick any input field (such as email, phone, name) as a unique identifier, as well as hidden or calculated fields.
Respondents can bypass this check by entering any type of content they want. For example, a respondent can enter an email address that is not theirs, and Tally can’t (yet) verify the ownership of the email address.
FAQ
Can I customize the error message when a respondent’s submission is denied?
No, at the moment, it is a default message. However, if you change the form language, the error message will also be translated.
Does the duplicate prevention feature take into account submissions before enabling it?
No. Only submissions made after enabling the feature are considered for duplicate prevention.
Does Tally support IP address collection upon form submission?
No, currently we don’t collect IP addresses.
In the future, we plan to add an email verification option to the Email field, which, in combination with "Prevent duplicate submissions," will offer the best protection. You can upvote email/phone number verification here →