SurveyJS

SurveyJS is a product suite of open-source JavaScript form libraries with native support for React, Angular, and Vue. It uses JSON for survey metadata and results. You have total freedom as to the backend, as it integrates with any server and database. You can use it to just load and run web forms from your storage, or set up a full-circle form management system fully integrated in your IT.

SurveyJS offers a lot of flexibility in controlling UI design through CSS classes, changing survey questions rendering and behavior, or even adding new question types.

The form builder comes with a CSS-based Theme Editor—a set of UI controls for form styling. Any alterations you make, from colors to fonts and layouts, are immediately visible. You can save your customized themes in JSON and reuse them across surveys.

You can render your custom surveys and forms as editable PDF files directly in a browser, and visualize survey results using interactive charts and tables. You may stick with the complete solution (four libraries) or use only the rendering Form Library. SurveyJS Form Library is a free and open source (under MIT license). However, professional full-time software developers support it.

You may freely use a full-scale demo to generate JSON schemas or integrate the form editor to your app using the Survey Creator library. The website offers 200+ demos and tutorials with code examples to assist you on achieving any task.