FHIR Questionnaire Logic Builder

A free, open-source visual builder for FHIR R4 Questionnaires. Build complex clinical questionnaires with drag-and-drop, then export valid FHIR JSON — no server required.

Key features

Drag-and-drop item tree — groups, items, nested structures
Conditional logic — enableWhen and enableWhenExpression (FHIRPath)
SDC variables — sdc-questionnaire-variable at questionnaire level
Calculated expressions — calculatedExpression with live FHIRPath evaluation
Patient presets — seed %age, %gender, %bmi and more
Answer types — text, integer, decimal, date, boolean, radio, select, open-choice, reference, quantity
FHIR JSON import and export — round-trip safe for all supported extensions
QuestionnaireResponse import and export
Display category — questionnaire-displayCategory (instructions / security / help)
Choice orientation — questionnaire-choiceOrientation (vertical / horizontal)
Entry format placeholders — sdc-questionnaire-entryFormat
Slider controls — questionnaire-sliderStepValue
Constraint validation — questionnaire-constraint with FHIRPath
Patient View — clean form preview without builder annotations

Built with vanilla JavaScript and fhirpath.js. No framework, no bundler, no backend. Source on GitHub.