SDC (Structured Data Capture) is the IG that takes a FHIR Questionnaire from a flat list of questions to a real interactive form, with skip logic, calculated expressions, and value-set-backed answer choices. The form builders that fully implement SDC are a smaller list than the form builders that claim to. Here are the five worth a real look for US hospital workflows in 2026.
For broader framing before going vendor by vendor, the 2026 Buyer's Guide to FHIR Form Builders for US Health Systems is the right primer, and more on FHIR for healthcare teams covers adjacent material.
LHC-Forms (from NLM)
LHC-Forms, developed by the Lister Hill National Center for Biomedical Communications at NLM, is the open-source form rendering library that powers many US healthcare apps. It implements SDC rendering precisely and handles LOINC panels natively, which makes it a strong pick for any American hospital workflow that depends on LOINC-based questionnaires. The rendering layer is JavaScript and integrates into React, Angular, or vanilla web apps.
Aidbox Forms (Formbox)
Formbox is the SDC form builder from the Aidbox product family. It provides both an authoring interface for clinical informaticists and a runtime rendering engine. American hospital teams running Aidbox often adopt Formbox because the integration with the FHIR storage is seamless and the SDC support is complete. Standalone use is supported as well.
Smile Digital Health Forms
Smile's form builder is part of its broader CDR Hub platform. It supports SDC fully, integrates with Smile's terminology service for live value set expansion, and includes an authoring UI suited to clinical informatics teams. American hospitals running Smile for FHIR storage get a coherent end-to-end forms experience.
Open SDC IGs from HL7
The HL7 SDC IGs themselves are not a product, but they come with reference implementations that several American hospital teams have adopted directly. The reference renderer in JavaScript handles the SDC profile correctly and serves as both an example and a starting point for custom implementations. The best FHIR Questionnaire tools for American clinical teams list covers more tools that build on these reference implementations.
Pathways Forms (Open mHealth)
Pathways Forms is the form rendering project from Open mHealth, focused on patient-facing forms in mobile contexts. American hospitals building patient apps that include questionnaires sometimes adopt Pathways for the mobile-first rendering. It is less of a clinician-facing tool, more of a patient-experience tool.
What "Real SDC Support" Means in 2026
Three things separate a real SDC implementation from a partial one. First, initial expressions and calculated expressions, which let the form populate fields from existing FHIR data or compute totals as the user answers. Second, enableWhen logic that handles complex conditions, including nested groups. Third, answer constraints that validate user input against value sets without manual code. A form builder that does all three is a real SDC tool. One that does only the first is a Questionnaire renderer with marketing.
For LOINC-specific scenarios, the 5 SDC form builders that actually render LOINC panels right goes deeper.
How to Pick
The decision usually splits along two axes. The first is clinical-facing vs patient-facing primary use case. The second is whether your hospital is already on a FHIR server (Aidbox, Smile) where the form builder is bundled, or whether you need a standalone tool. Pick a product whose SDC support you have verified by building a real form, not by reading a feature list.
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