Link Surveys

Data Prefilling in Link Surveys

Data prefilling via the URL allows you to increase conversion rate by prefilling data you already have in a different system.


URL prefilling of data comes in handy when you:

  • Have data for some of the respondents, but not all
  • Have data in a different system (e.g. your database) and want to add it to the user profile in Formbricks
  • Want to embed the first question in an email and increase conversion by prefilling the choice

Quick Example

Example URL

How it works

To prefill the first question of a survey, append ?question_id=answer at the end of the survey URL. The answer has to match the expected type of the question. For example, if the first question is a rating question, the answer has to be a number. If the first question is a single select question, the answer has to be a string.

Please make sure the answer is URL encoded.

Where do I find my question Id?

You find the questionId in the Advanced Settings at the bottom of each question card in the Survey Editor. As you see, you can update the questionId to any string you like. However, once you published your survey, this questionId cannot be updated anymore:

The question Id is located at the bottom of each question card in the survey editor.


Here are a few examples to get you started:

Rating Question

Translates to 5 stars / points / emojis

NPS Question

Translates to an NPS rating of 10

Single Select Question (Radio)

Chooses the option 'Very disappointed' in the single select question. The string has to be identical to the option in your question

Multi Select Question (Checkbox)

Selects three options 'Sun, Palms and Beach' in the multi select question. The strings have to be identical to the options in your question

Open Text Question

Adds 'I love Formbricks' as the answer to the open text question

CTA Question

Adds 'clicked' as the answer to the CTA question. Alternatively, you can set it to 'dismissed' to skip the question.


Make sure that the answer in the URL matches the expected type for the first question.

The URL validation works as follows:

  • For Rating or NPS questions, the response is parsed as a number and verified if it's accepted by the schema.
  • For CTA type questions, the valid values are "clicked" (main CTA) and "dismissed" (skip CTA).
  • For Consent type questions, the valid values are "accepted" (consent given) and "dismissed" (consent not given).
  • All other question types are strings.

You’re good to go! 🎉

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