What Formhaus covers

What the definition format, the engine and the renderers do, what they leave to your app, and where another library fits better.

Covered

Area	What you get	Guide
Definitions	Plain JSON with a JSON Schema. Agents generate and check it, apps store it in a database, and native renderers read the same file under the specification.	Specification, MCP server
React and Vue	FormRenderer with built-in fields, HeadlessFormRenderer and useFormEngine	Choose a renderer
Multi-step	Steps, Back and Next, skip, welcome screen, lifecycle hooks	Multi-Step Forms
Conditions and routes	show and showAny on fields, sections and steps, routes between branches	Conditional Fields, Route between branches
Groups	Repeatable items with item count rules and per-item conditions	Repeatable Groups
Matrix	A section drawn as a grid of radio or multiselect rows	Matrix
Scales	scale, NPS and rating	Scale, Rating
Answer recall	{{key}} tokens that show an earlier answer in later texts	Answer recall
i18n	Message and label catalogs, translation keys, overlays	Translations
Accessibility	Native inputs, labels and hints tied by aria-describedby, aria-invalid, autocomplete tokens, error summary with focus	Autofill, Error summary
Server validation	validateSubmission() runs the same rules and type checks on the server as the browser	Server-side Validation
Events	form_viewed, step_completed, field_error, form_submitted and other lifecycle events	Form events
Hidden fields	Values from the URL, referrer, page, language, time zone, device or host	Value sources
Files	A File in the browser, a reference such as an upload id on the server	File, Cloud files
Cloud	Optional hosted endpoint, hosted form page and file uploads	Get an Endpoint

Not covered

Gap	Workaround
Calculated values or scoring inside the definition	Add a hidden field and set it from app code with setValue. Compute it again on the server: validateSubmission() checks only its type and rules. See Derived values.
Nested groups	A group cannot contain a group or a section (invalid-nesting). Use two top-level groups, or a custom field type inside the item that holds the inner list.
Files inside groups	A group cannot contain a file or hidden field (invalid-nesting). Put the file field outside the group, or use a custom field type in the item that uploads the file and stores its reference as text.
Payment card fields	There is no card field type. Use the payment provider's own elements next to the form. Formhaus Cloud refuses hosted forms with cc-* autocomplete tokens.
Signatures, rich text, address autocomplete with maps	Write a custom field type and pass its component through components. See also custom components.
Offline drafts with sync	Save onValuesChange values in your own storage, pass them back as initialValues, and queue the submit in app code. FormhausForm keeps a draft in sessionStorage of the tab, with no sync.
Pixel-unique design	Replace field components through components, or use HeadlessFormRenderer or FormEngine with your own markup.

When another library fits better

• One hand-written form with custom UI and no JSON definition: a form-state library such as React Hook Form is smaller. See vs react-hook-form.
• Large survey programs that need expressions, calculated values, result dashboards or a drag-and-drop editor for non-developers: a survey platform covers them. See vs SurveyJS.