improvement(contact): add Turnstile CAPTCHA, honeypot, and robustness fixes

- Add Cloudflare Turnstile with graceful degradation: when the widget
  fails to load (ad blockers, iOS privacy, corporate DNS), submissions
  fall through to a tighter rate-limit bucket rather than hard-blocking
- Add honeypot field to filter automated submissions without user impact
- Add separate CAPTCHA_UNAVAILABLE_RATE_LIMIT bucket (3/min) for the
  no-captcha path so spam via ad-blocker bypass remains expensive
- Pass expectedHostname to verifyTurnstileToken to close cross-site
  token reuse gap
- Add SITE_HOSTNAME as module-level constant (avoid URL parsing per req)
- Wire onExpire/onError/onUnsupported callbacks so token expiry during
  slow form-filling falls back gracefully instead of showing a captcha error
- Add getResponsePromise(30_000) timeout to prevent indefinite hang on
  network blips
- Add size: 'invisible' to Turnstile options (required for execute mode)
- Move turnstile.ts to lib/core/security/ alongside csp/encryption/input-validation
- Switch all CSS to --landing-* variables throughout contact form
- Move error display inline next to label with truncation in LandingField
- Add labelClassName prop to LandingField for context-specific overrides
- Simplify contact page to single-column max-w-[640px] layout

Author: waleedlatif1

apps/sim/app/(landing)/components/contact/contact-form.tsx

@@ -1,10 +1,13 @@
 'use client'
 
-import { useState } from 'react'
+import { useEffect, useRef, useState } from 'react'
+import { Turnstile, type TurnstileInstance } from '@marsidev/react-turnstile'
+import { toError } from '@sim/utils/errors'
 import { useMutation } from '@tanstack/react-query'
+import Link from 'next/link'
 import { Combobox, Input, Textarea } from '@/components/emcn'
 import { Check } from '@/components/emcn/icons'
-import { cn } from '@/lib/core/utils/cn'
+import { getEnv } from '@/lib/core/config/env'
 import { captureClientEvent } from '@/lib/posthog/client'
 import {
   CONTACT_TOPIC_OPTIONS,
@@ -34,12 +37,28 @@ const INITIAL_FORM_STATE: ContactFormState = {
   message: '',
 }
 
-const COMBOBOX_TOPICS = [...CONTACT_TOPIC_OPTIONS]
-
 const LANDING_INPUT =
-  'h-[36px] rounded-[5px] border border-[var(--border-1)] bg-[var(--surface-5)] px-3 font-[430] font-season text-[14px] text-[var(--text-primary)] outline-none transition-colors placeholder:text-[var(--text-muted)]'
+  'h-[40px] rounded-[5px] border border-[var(--landing-bg-elevated)] bg-[var(--landing-bg-surface)] px-3 font-[430] font-season text-[14px] text-[var(--landing-text)] outline-none transition-colors placeholder:text-[var(--landing-text-muted)] focus:border-[var(--landing-border-strong)]'
+
+const LANDING_TEXTAREA =
+  'min-h-[140px] rounded-[5px] border border-[var(--landing-bg-elevated)] bg-[var(--landing-bg-surface)] px-3 py-2.5 font-[430] font-season text-[14px] text-[var(--landing-text)] outline-none transition-colors placeholder:text-[var(--landing-text-muted)] focus:border-[var(--landing-border-strong)]'
+
+const LANDING_COMBOBOX =
+  'h-[40px] rounded-[5px] border border-[var(--landing-bg-elevated)] bg-[var(--landing-bg-surface)] px-3 font-[430] font-season text-[14px] text-[var(--landing-text)] hover:bg-[var(--landing-bg-surface)] focus-within:border-[var(--landing-border-strong)]'
+
+const LANDING_SUBMIT =
+  'flex h-[40px] w-full items-center justify-center rounded-[5px] border border-[var(--landing-text-subtle)] bg-[var(--landing-text-subtle)] font-[430] font-season text-[14px] text-[var(--landing-text-dark)] transition-colors hover:border-[var(--landing-bg-hover)] hover:bg-[var(--landing-bg-hover)] disabled:cursor-not-allowed disabled:opacity-60'
+
+const LANDING_LABEL =
+  'font-[500] font-season text-[13px] text-[var(--landing-text)] tracking-[0.02em]'
 
-async function submitContactRequest(payload: ContactRequestPayload) {
+interface SubmitContactRequestInput extends ContactRequestPayload {
+  website: string
+  captchaToken?: string
+  captchaUnavailable?: boolean
+}
+
+async function submitContactRequest(payload: SubmitContactRequestInput) {
   const response = await fetch('/api/contact', {
     method: 'POST',
     headers: { 'Content-Type': 'application/json' },
@@ -59,9 +78,7 @@ async function submitContactRequest(payload: ContactRequestPayload) {
 }
 
 export function ContactForm() {
-  const [form, setForm] = useState<ContactFormState>(INITIAL_FORM_STATE)
-  const [errors, setErrors] = useState<ContactErrors>({})
-  const [submitSuccess, setSubmitSuccess] = useState(false)
+  const turnstileRef = useRef<TurnstileInstance>(null)
 
   const contactMutation = useMutation({
     mutationFn: submitContactRequest,
@@ -71,8 +88,22 @@ export function ContactForm() {
       setErrors({})
       setSubmitSuccess(true)
     },
+    onError: () => {
+      turnstileRef.current?.reset()
+    },
   })
 
+  const [form, setForm] = useState<ContactFormState>(INITIAL_FORM_STATE)
+  const [errors, setErrors] = useState<ContactErrors>({})
+  const [submitSuccess, setSubmitSuccess] = useState(false)
+  const [website, setWebsite] = useState('')
+  const [widgetReady, setWidgetReady] = useState(false)
+  const [turnstileSiteKey, setTurnstileSiteKey] = useState<string | undefined>()
+
+  useEffect(() => {
+    setTurnstileSiteKey(getEnv('NEXT_PUBLIC_TURNSTILE_SITE_KEY'))
+  }, [])
+
   function updateField<TField extends keyof ContactFormState>(
     field: TField,
     value: ContactFormState[TField]
@@ -91,7 +122,7 @@ export function ContactForm() {
     }
   }
 
-  function handleSubmit(event: React.FormEvent<HTMLFormElement>) {
+  async function handleSubmit(event: React.FormEvent<HTMLFormElement>) {
     event.preventDefault()
     if (contactMutation.isPending) return
 
@@ -113,32 +144,48 @@ export function ContactForm() {
       return
     }
 
-    contactMutation.mutate(parsed.data)
+    let captchaToken: string | undefined
+    let captchaUnavailable: boolean | undefined
+    const widget = turnstileRef.current
+
+    if (turnstileSiteKey) {
+      if (widgetReady && widget) {
+        try {
+          widget.reset()
+          widget.execute()
+          captchaToken = await widget.getResponsePromise(30_000)
+        } catch {
+          captchaUnavailable = true
+        }
+      } else {
+        captchaUnavailable = true
+      }
+    }
+
+    contactMutation.mutate({ ...parsed.data, website, captchaToken, captchaUnavailable })
   }
 
   const submitError = contactMutation.isError
-    ? contactMutation.error instanceof Error
-      ? contactMutation.error.message
-      : 'Failed to send message. Please try again.'
+    ? toError(contactMutation.error).message || 'Failed to send message. Please try again.'
     : null
 
   if (submitSuccess) {
     return (
-      <div className='flex min-h-[460px] flex-col items-center justify-center rounded-[8px] border border-[var(--border-1)] bg-[var(--surface-5)] px-8 py-16 text-center'>
-        <div className='flex h-16 w-16 items-center justify-center rounded-full border border-[var(--border)] bg-[var(--bg-subtle)] text-[var(--text-primary)]'>
+      <div className='flex min-h-[460px] flex-col items-center justify-center px-8 py-16 text-center'>
+        <div className='flex h-16 w-16 items-center justify-center rounded-full border border-[var(--landing-bg-elevated)] bg-[var(--landing-bg-surface)] text-[var(--landing-text)]'>
           <Check className='h-8 w-8' />
         </div>
-        <h2 className='mt-6 font-[430] font-season text-[24px] text-[var(--text-primary)] leading-[1.2] tracking-[-0.02em]'>
+        <h2 className='mt-6 font-[430] font-season text-[24px] text-[var(--landing-text)] leading-[1.2] tracking-[-0.02em]'>
           Message received
         </h2>
-        <p className='mt-3 max-w-sm font-season text-[14px] text-[var(--text-secondary)] leading-[1.6]'>
+        <p className='mt-3 max-w-sm font-season text-[14px] text-[var(--landing-text-body)] leading-[1.6]'>
           Thanks for reaching out. We've sent a confirmation to your inbox and will get back to you
           shortly.
         </p>
         <button
           type='button'
           onClick={() => setSubmitSuccess(false)}
-          className='mt-6 font-season text-[13px] text-[var(--text-primary)] underline underline-offset-2 transition-opacity hover:opacity-80'
+          className='mt-6 font-season text-[13px] text-[var(--landing-text)] underline underline-offset-2 transition-opacity hover:opacity-80'
         >
           Send another message
         </button>
@@ -147,12 +194,33 @@ export function ContactForm() {
   }
 
   return (
-    <form
-      onSubmit={handleSubmit}
-      className='flex flex-col gap-4 rounded-[8px] border border-[var(--border-1)] bg-[var(--surface-5)] p-6 sm:p-8'
-    >
-      <div className='grid gap-4 sm:grid-cols-2'>
-        <LandingField htmlFor='contact-name' label='Name' error={errors.name}>
+    <form onSubmit={handleSubmit} className='flex flex-col gap-5'>
+      {/* Honeypot */}
+      <div
+        aria-hidden='true'
+        className='pointer-events-none absolute left-[-9999px] h-px w-px overflow-hidden opacity-0'
+      >
+        <label htmlFor='contact-website'>Website</label>
+        <input
+          id='contact-website'
+          name='website'
+          type='text'
+          tabIndex={-1}
+          autoComplete='off'
+          value={website}
+          onChange={(event) => setWebsite(event.target.value)}
+          data-lpignore='true'
+          data-1p-ignore='true'
+        />
+      </div>
+
+      <div className='grid gap-5 sm:grid-cols-2'>
+        <LandingField
+          htmlFor='contact-name'
+          label='Name'
+          error={errors.name}
+          labelClassName={LANDING_LABEL}
+        >
           <Input
             id='contact-name'
             value={form.name}
@@ -161,7 +229,12 @@ export function ContactForm() {
             className={LANDING_INPUT}
           />
         </LandingField>
-        <LandingField htmlFor='contact-email' label='Email' error={errors.email}>
+        <LandingField
+          htmlFor='contact-email'
+          label='Email'
+          error={errors.email}
+          labelClassName={LANDING_LABEL}
+        >
           <Input
             id='contact-email'
             type='email'
@@ -173,8 +246,14 @@ export function ContactForm() {
         </LandingField>
       </div>
 
-      <div className='grid gap-4 sm:grid-cols-2'>
-        <LandingField htmlFor='contact-company' label='Company' optional error={errors.company}>
+      <div className='grid gap-5 sm:grid-cols-2'>
+        <LandingField
+          htmlFor='contact-company'
+          label='Company'
+          optional
+          error={errors.company}
+          labelClassName={LANDING_LABEL}
+        >
           <Input
             id='contact-company'
             value={form.company}
@@ -183,21 +262,31 @@ export function ContactForm() {
             className={LANDING_INPUT}
           />
         </LandingField>
-        <LandingField htmlFor='contact-topic' label='Topic' error={errors.topic}>
+        <LandingField
+          htmlFor='contact-topic'
+          label='Topic'
+          error={errors.topic}
+          labelClassName={LANDING_LABEL}
+        >
           <Combobox
-            options={COMBOBOX_TOPICS}
+            options={CONTACT_TOPIC_OPTIONS}
             value={form.topic}
             selectedValue={form.topic}
             onChange={(value) => updateField('topic', value as ContactRequestPayload['topic'])}
             placeholder='Select a topic'
             editable={false}
             filterOptions={false}
-            className='h-[36px] rounded-[5px] px-3 font-[430] font-season text-[14px]'
+            className={LANDING_COMBOBOX}
           />
         </LandingField>
       </div>
 
-      <LandingField htmlFor='contact-subject' label='Subject' error={errors.subject}>
+      <LandingField
+        htmlFor='contact-subject'
+        label='Subject'
+        error={errors.subject}
+        labelClassName={LANDING_LABEL}
+      >
         <Input
           id='contact-subject'
           value={form.subject}
@@ -207,33 +296,53 @@ export function ContactForm() {
         />
       </LandingField>
 
-      <LandingField htmlFor='contact-message' label='Message' error={errors.message}>
+      <LandingField
+        htmlFor='contact-message'
+        label='Message'
+        error={errors.message}
+        labelClassName={LANDING_LABEL}
+      >
         <Textarea
           id='contact-message'
           value={form.message}
           onChange={(event) => updateField('message', event.target.value)}
           placeholder='Share details so we can help as quickly as possible'
-          className='min-h-[140px] rounded-[5px] border border-[var(--border-1)] bg-[var(--surface-5)] px-3 py-2.5 font-[430] font-season text-[14px] text-[var(--text-primary)] outline-none transition-colors placeholder:text-[var(--text-muted)]'
+          className={LANDING_TEXTAREA}
         />
       </LandingField>
 
+      {turnstileSiteKey ? (
+        <Turnstile
+          ref={turnstileRef}
+          siteKey={turnstileSiteKey}
+          options={{ execution: 'execute', appearance: 'execute', size: 'invisible' }}
+          onWidgetLoad={() => setWidgetReady(true)}
+          onExpire={() => setWidgetReady(false)}
+          onError={() => setWidgetReady(false)}
+          onUnsupported={() => setWidgetReady(false)}
+        />
+      ) : null}
+
       {submitError ? (
         <p role='alert' className='font-season text-[13px] text-[var(--text-error)]'>
           {submitError}
         </p>
       ) : null}
 
-      <button
-        type='submit'
-        disabled={contactMutation.isPending}
-        className={cn(
-          'flex h-[40px] w-full items-center justify-center rounded-[5px] bg-[var(--text-primary)]',
-          'font-[430] font-season text-[14px] text-[var(--bg)] transition-opacity',
-          'hover:opacity-90 disabled:cursor-not-allowed disabled:opacity-60'
-        )}
-      >
+      <button type='submit' disabled={contactMutation.isPending} className={LANDING_SUBMIT}>
         {contactMutation.isPending ? 'Sending...' : 'Send message'}
       </button>
+
+      <p className='text-center font-season text-[12px] text-[var(--landing-text-muted)] leading-[1.6]'>
+        By submitting, you agree to our{' '}
+        <Link
+          href='/privacy'
+          className='text-[var(--landing-text)] underline underline-offset-2 transition-opacity hover:opacity-80'
+        >
+          Privacy Policy
+        </Link>
+        .
+      </p>
     </form>
   )
 }

apps/sim/app/(landing)/components/forms/landing-field.tsx

@@ -6,29 +6,44 @@ interface LandingFieldProps {
   optional?: boolean
   error?: string
   children: React.ReactNode
+  /** Replaces the default label className. */
+  labelClassName?: string
 }
 
-export function LandingField({ label, htmlFor, optional, error, children }: LandingFieldProps) {
+const DEFAULT_LABEL_CLASSNAME =
+  'font-[430] font-season text-[13px] text-[var(--text-secondary)] tracking-[0.02em]'
+
+export function LandingField({
+  label,
+  htmlFor,
+  optional,
+  error,
+  children,
+  labelClassName,
+}: LandingFieldProps) {
   const errorId = error ? `${htmlFor}-error` : undefined
   const describedChild =
     errorId && isValidElement<{ 'aria-describedby'?: string; 'aria-invalid'?: boolean }>(children)
       ? cloneElement(children, { 'aria-describedby': errorId, 'aria-invalid': true })
       : children
   return (
     <div className='flex flex-col gap-1.5'>
-      <label
-        htmlFor={htmlFor}
-        className='font-[430] font-season text-[13px] text-[var(--text-secondary)] tracking-[0.02em]'
-      >
-        {label}
-        {optional ? <span className='ml-1 text-[var(--text-muted)]'>(optional)</span> : null}
-      </label>
+      <div className='flex min-h-[18px] items-baseline justify-between gap-3'>
+        <label htmlFor={htmlFor} className={labelClassName ?? DEFAULT_LABEL_CLASSNAME}>
+          {label}
+          {optional ? <span className='ml-1 text-[var(--text-muted)]'>(optional)</span> : null}
+        </label>
+        {error ? (
+          <span
+            id={errorId}
+            role='alert'
+            className='truncate font-season text-[12px] text-[var(--text-error)]'
+          >
+            {error}
+          </span>
+        ) : null}
+      </div>
       {describedChild}
-      {error ? (
-        <p id={errorId} role='alert' className='text-[12px] text-[var(--text-error)]'>
-          {error}
-        </p>
-      ) : null}
     </div>
   )
 }