survey-library

SurveyJS is the library that does it. Drag-and-drop form builder, conditional logic, 20+ question types, all rendered inside your React/Angular/Vue/jQuery app.

The survey-library (the rendering engine) is MIT licensed and free. You can build forms, collect responses, and do conditional logic without paying anything. But the visual form builder (survey-creator), the drag-and-drop UI that non-developers use to design forms, requires a commercial license starting at $899/year for one developer.

There's no cloud service to host. SurveyJS is a client-side library you embed in your app. Your data stays on your servers. The form definitions are JSON objects you store however you want. Solo developers: the free library is powerful enough to build complex forms in code. You don't need the visual builder if you're comfortable writing JSON. Small teams: the $899/year builder license pays for itself the moment a non-developer needs to create forms. Growing teams: the Pro license at $2,499/year adds PDF export and advanced analytics.

The catch: the split between free library and paid builder is confusing. The library is free, but the moment someone says "I want a drag-and-drop editor," you're in paid territory.