Stop hand-coding form logic
Form logic, not form code
Declare what your form should do. Formidable handles how it does it.
FEEL Expressions
Friendly Enough Expression Language powers conditional visibility, dynamic requirements, and field-level logic — no JavaScript needed.
"visibleWhen": "age >= 65"
"requiredWhen": "hasInsurance = true"
"visibleWhen": "country = \"US\""Behavior
Fields appear, become required, or hide based on user input — evaluated in real-time.
Validation Rules
Express complex validation as declarative rules with custom error messages. Reference other fields, use date math, regex patterns.
"validations": [{
"rule": "value >= minAge",
"message": "Must be at least {minAge}"
}]Behavior
Validation runs on blur and submit. Error messages support field references and template variables.
Computed Fields
Calculated values that update automatically as users fill out the form. Scores, totals, risk categories — all declarative.
"computed": {
"total": {
"expression": "quantity * unitPrice",
"label": "Order Total"
}
}Behavior
Computed values recalculate instantly. Use them in visibility rules, validation, or display them as read-only fields.
See it in action
Watch how Formidable transforms a conversation into production-ready forms in minutes.
Build vs. Buy
You could hand-code every form feature. Or describe what you need and let AI handle the rest.
Export to your stack
Build once, export anywhere. Formidable generates specs in the formats your tools already use.
Forma
Native spec with FEEL expressions, pages, computed fields, and full rendering support.
JSON Schema
Standard JSON Schema with validation constraints for backend integration.
Zod
TypeScript-first validation with generated Zod schemas for type-safe form handling.
Start building smarter forms
From conversation to production-ready form spec — with validation, logic, and export built in.
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