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Response Piping

Response piping lets you insert answers from earlier questions into the text of later questions, creating a more personalized survey experience.

How It Works​

Piping is powered by the instructions system. When you reference a previous question's value in a label or text, the Survey Engine creates a dependency between the two components. The generated state machine re-evaluates the label whenever the referenced value changes, so piped text updates in real time as the respondent fills in the survey.

Using Piping in the Editor​

The rich text editor (TipTap) for question labels and info elements supports mentions — type @ to see a list of available questions to reference. Selecting a question inserts a piped reference that will be replaced with the respondent's answer at runtime.

How Piping Works Under the Hood​

Any content (question labels, descriptions, info elements) that contains {{ ... }} (double curly braces) is treated as containing format instructions. The frontend extracts the content between the braces as a JavaScript expression and sends it as a format instruction to the engine.

For example, when you use the @ mention to insert a reference to Qname, the editor produces content like:

Thank you, {{Qname.value}}!

The frontend:

  1. Scans the content for {{ ... }} patterns
  2. Extracts each expression (e.g., Qname.value) as a format instruction
  3. Sends these format instructions to the Survey Engine
  4. The engine evaluates the expressions, detects dependencies, and updates the displayed text whenever a referenced value changes

Examples​

Personalized greeting:

Thank you, {{Qname.value}}! Based on your experience at {{Qrestaurant.value}}, we'd like to ask a few more questions.

The respondent sees their actual name and restaurant name inserted into the text.

Dynamic follow-up:

You mentioned you've been a customer for {{Qyears.value}} years. How has your experience changed over that time?

What Can Be Piped​

  • Text question values — the respondent's typed answer
  • Number values — numeric answers
  • Choice labels — the label text of the selected option
  • Date values — selected dates

Piped references can be used in:

  • Question labels
  • Question descriptions
  • Info element text (text display)
  • Page titles