Generate a form plugin with conditional logic fields
Conditional logic is where form builders quietly get expensive. Gravity, WPForms, Formidable all charge for it, and the rule engines they ship are powerful but often more than you need.
If your logic is "if answer to Q1 is Yes, show Q3 and Q4", a generated plugin with a small rules file is simpler, faster, and validates on the server so a motivated visitor cannot DevTools their way past the rules.
Why generate it instead of installing an existing plugin?
Conditional logic in Gravity is part of the base plan (good) but the builder UX means rules live in a UI nobody audits. WPForms puts it behind Pro (€199+/year). Formidable bundles it. None of them validate server-side strictly — the rule is enforced in the browser, and the server only checks presence of fields, not "was this field legitimately visible when you answered it?".
A custom plugin declares rules in code or a JSON config. The frontend hides/shows fields for UX, and the backend re-evaluates every rule before saving. If a visitor submits a field that was supposed to be hidden, we reject the submission with a 422.
This makes the form both friendlier and harder to abuse. Useful for surveys where answer-path matters, for lead-qualification forms, for multi-path contact routing.
Example prompt
This is the kind of description that generates this plugin. You can start from it and tweak whatever you need before hitting generate.
Plugin name: Acme Smart Form
Fields:
1. are_you_business (radio: yes/no) — required
2. company_name (text) — shown only if are_you_business == yes
3. personal_use_case (textarea) — shown only if are_you_business == no
4. email (email) — always required
5. volume (select) — shown only if are_you_business == yes AND company_name not empty
Rules stored as a JSON array in a PHP constant.
Frontend: simple JS walks the rules on change events, toggles visibility.
Backend: /wp-json/acme/v1/smart-form POST.
- Re-runs the rules over POST payload.
- A field that was supposed to be hidden but arrives with a value -> 422.
- A required-when-visible field missing -> 422 with field-level errors.
Errors rendered inline under each field.
Store accepted submissions to wp_acme_smartform.What the generated plugin typically includes
- Rules declared as JSON in one PHP constant, easy to edit
- Shared rule evaluator used by both frontend and backend
- Field-level error responses from REST endpoint
- Frontend vanilla JS that toggles visibility without re-render
- Server-side strict mode: rejects impossible payloads
- Admin page listing submissions with the path taken
Rule language is as rich as you describe. Simple equality and boolean logic covers most cases; if you need regex or math, include that in the prompt.
Frequently asked questions
Why re-evaluate on the server?
Because a browser can be lying. A strict server rejects payloads where a supposedly hidden field arrived with data, which closes a common survey-gaming vector.
Can the rules reference previous submissions?
Yes if the visitor is logged in. Describe the cross-submission rule in the prompt and the plugin will load the history before evaluating.