diff --git a/apps/sim/app/(landing)/demo/components/demo-booking/demo-booking.tsx b/apps/sim/app/(landing)/demo/components/demo-booking/demo-booking.tsx
index 681858f1a55..4b7a499704d 100644
--- a/apps/sim/app/(landing)/demo/components/demo-booking/demo-booking.tsx
+++ b/apps/sim/app/(landing)/demo/components/demo-booking/demo-booking.tsx
@@ -24,34 +24,22 @@ interface DemoBookingProps {
 }
 
 /**
- * The demo page's right column - a two-step booking card and the only client
- * island on the page. It owns the card chrome (`rounded-lg`, `--surface-2`,
- * {@link chipBorderShadowRing}) and the step.
+ * The demo page's right column: a two-step booking card and the only client
+ * island on the page. Owns the card chrome and the step transition.
  *
- * Both steps live side by side in a sliding track: the form is panel 1, the
- * scheduler panel 2. Submitting slides one-way to the scheduler
- * (`translateX(-100%)`) at the platform's `duration-200 ease-out` (a refresh
- * restarts the flow). The form stays mounted (it drives the card height); the
- * off-screen panel is `inert` so it's out of tab/AT order.
+ * The form (panel 1) and scheduler (panel 2) sit side by side in a sliding
+ * track; submitting slides one-way to the scheduler at `duration-200 ease-out`.
+ * The form stays mounted and drives the card height, so the card never resizes
+ * across the transition; a `ResizeObserver` keeps the pinned height in sync as
+ * the form grows (inline error, phone breakpoint). The off-screen panel is
+ * `inert` (out of tab/AT order) and the scheduler lazy-mounts on submit,
+ * preloaded on first form focus.
  *
- * The card is pinned to the form's measured height so it never resizes across
- * the form→calendar transition (the Cal embed self-sizes its own iframe via
- * postMessage, so this is purely to keep the card's height stable). A
- * `ResizeObserver` keeps it in sync as the form grows (an inline error, a phone
- * breakpoint). The scheduler fills its panel and lazy-mounts on submit (preloaded
- * on first form focus).
- *
- * Exception on phones (`max-sm`): once the scheduler is showing, the form-height
- * pin is overridden to `80svh` so the Cal booker gets a real viewport instead of
- * being crammed into the short form height - which caged the self-sizing iframe
- * behind `overflow:auto` and made its day/time slots tiny and hard to tap. The
- * pin is published as the `--demo-card-h` CSS var rather than an inline `height`
- * so the `max-sm` class can win (a media-query class can't override an inline
- * style height). `svh` keeps the height steady as the mobile URL bar shows/hides,
- * so the tap targets never shift.
- *
- * (Wiring the lead to a backend on submit slots in here - capture it before or
- * alongside `setLead`.)
+ * The pin is published as the `--demo-card-h` CSS var (not an inline `height`)
+ * so a `max-sm:h-[80svh]` class can override it once the scheduler shows — the
+ * Cal booker needs a real viewport on phones instead of being crammed into the
+ * short form height. `svh` keeps tap targets from shifting as the mobile URL bar
+ * hides/shows.
  */
 export function DemoBooking({ className }: DemoBookingProps) {
   const [lead, setLead] = useState<DemoLead | null>(null)
diff --git a/apps/sim/app/(landing)/demo/components/demo-form/demo-form.tsx b/apps/sim/app/(landing)/demo/components/demo-form/demo-form.tsx
index dba60f052af..370e1ecb436 100644
--- a/apps/sim/app/(landing)/demo/components/demo-form/demo-form.tsx
+++ b/apps/sim/app/(landing)/demo/components/demo-form/demo-form.tsx
@@ -6,6 +6,7 @@ import {
   DEMO_REQUEST_COMPANY_SIZE_OPTIONS,
   type DemoRequestBody,
 } from '@/lib/api/contracts/demo-requests'
+import { isFreeEmailDomain } from '@/lib/messaging/email/free-email'
 import { quickValidateEmail } from '@/lib/messaging/email/validation'
 import { useSubmitDemoRequest } from '@/hooks/queries/demo-requests'
 
@@ -175,7 +176,9 @@ export function DemoForm({ onComplete }: DemoFormProps) {
   }, [])
 
   const trimmedEmail = form.email.trim()
-  const emailIsValid = trimmedEmail.length > 0 && quickValidateEmail(trimmedEmail).isValid
+  const emailFormatValid = trimmedEmail.length > 0 && quickValidateEmail(trimmedEmail).isValid
+  const emailIsFreeDomain = isFreeEmailDomain(trimmedEmail)
+  const emailIsValid = emailFormatValid && !emailIsFreeDomain
   const canSubmit =
     emailIsValid &&
     form.firstName.trim().length > 0 &&
@@ -184,20 +187,23 @@ export function DemoForm({ onComplete }: DemoFormProps) {
     form.companySize.length > 0
 
   /**
-   * Only surface a format error once the value looks like an address attempt
-   * (contains `@`) so the field doesn't flash an error on the first keystroke.
+   * Surface an error only once the value looks like an address attempt (contains
+   * `@`) so the field doesn't flash on the first keystroke, and distinguish a
+   * malformed address from a personal one so the visitor knows to switch to a
+   * work email — matching the server's work-email requirement.
    */
-  const emailError =
-    form.email.includes('@') && !emailIsValid ? 'Enter a valid work email address.' : undefined
+  const emailError = !form.email.includes('@')
+    ? undefined
+    : !emailFormatValid
+      ? 'Enter a valid work email address.'
+      : emailIsFreeDomain
+        ? 'Please use your work email address.'
+        : undefined
 
   const handleSubmit = () => {
     if (!canSubmit) return
 
-    // Notify sales of the inbound demo (route emails the sales inbox, replying to
-    // the visitor - no email is sent to the visitor). Fire-and-forget so a failed
-    // or rate-limited notification never blocks the visitor from scheduling; the
-    // company-size value originates from the contract's own options, so it is a
-    // valid payload value.
+    // Best-effort sales notification — fire-and-forget so it never blocks scheduling.
     submitDemoRequest.mutate({
       firstName: form.firstName.trim(),
       lastName: form.lastName.trim(),
diff --git a/apps/sim/app/(landing)/demo/components/demo-scheduler/demo-scheduler.tsx b/apps/sim/app/(landing)/demo/components/demo-scheduler/demo-scheduler.tsx
index eea5a3d0b9d..c86d0ea9fbf 100644
--- a/apps/sim/app/(landing)/demo/components/demo-scheduler/demo-scheduler.tsx
+++ b/apps/sim/app/(landing)/demo/components/demo-scheduler/demo-scheduler.tsx
@@ -33,9 +33,7 @@ export function DemoScheduler({ lead }: DemoSchedulerProps) {
   useEffect(() => {
     getCalApi({ namespace: CAL_NAMESPACE }).then((cal) => {
       cal('ui', {
-        theme: 'light',
         hideEventTypeDetails: true,
-        layout: 'month_view',
         styles: { branding: { brandColor: CAL_BRAND_COLOR } },
       })
     })
@@ -58,6 +56,8 @@ export function DemoScheduler({ lead }: DemoSchedulerProps) {
             name: lead.name,
             email: lead.email,
             notes: lead.notes,
+            theme: 'light',
+            'ui.color-scheme': 'light',
             layout: 'month_view',
             useSlotsViewOnSmallScreen: 'true',
           }}
diff --git a/apps/sim/lib/api/contracts/demo-requests.ts b/apps/sim/lib/api/contracts/demo-requests.ts
index 55fe54d4dbd..47fb32a7088 100644
--- a/apps/sim/lib/api/contracts/demo-requests.ts
+++ b/apps/sim/lib/api/contracts/demo-requests.ts
@@ -1,11 +1,9 @@
-import freeEmailDomains from 'free-email-domains'
 import { z } from 'zod'
 import { defineRouteContract } from '@/lib/api/contracts/types'
+import { isFreeEmailDomain } from '@/lib/messaging/email/free-email'
 import { NO_EMAIL_HEADER_CONTROL_CHARS_REGEX } from '@/lib/messaging/email/utils'
 import { quickValidateEmail } from '@/lib/messaging/email/validation'
 
-const FREE_EMAIL_DOMAINS = new Set(freeEmailDomains)
-
 export const DEMO_REQUEST_COMPANY_SIZE_VALUES = [
   '1_10',
   '11_50',
@@ -46,10 +44,7 @@ export const demoRequestSchema = z.object({
     .max(320)
     .transform((value) => value.toLowerCase())
     .refine((value) => quickValidateEmail(value).isValid, 'Enter a valid work email')
-    .refine((value) => {
-      const domain = value.split('@')[1]
-      return domain ? !FREE_EMAIL_DOMAINS.has(domain) : true
-    }, 'Please use your work email address'),
+    .refine((value) => !isFreeEmailDomain(value), 'Please use your work email address'),
   phoneNumber: z
     .string()
     .trim()
diff --git a/apps/sim/lib/messaging/email/free-email.test.ts b/apps/sim/lib/messaging/email/free-email.test.ts
new file mode 100644
index 00000000000..206bd8b015b
--- /dev/null
+++ b/apps/sim/lib/messaging/email/free-email.test.ts
@@ -0,0 +1,27 @@
+/**
+ * @vitest-environment node
+ */
+import { describe, expect, it } from 'vitest'
+import { isFreeEmailDomain } from './free-email'
+
+describe('isFreeEmailDomain', () => {
+  it('returns true for known free/personal providers', () => {
+    expect(isFreeEmailDomain('jane@gmail.com')).toBe(true)
+    expect(isFreeEmailDomain('jane@yahoo.com')).toBe(true)
+    expect(isFreeEmailDomain('jane@hotmail.com')).toBe(true)
+  })
+
+  it('returns false for work domains', () => {
+    expect(isFreeEmailDomain('jane@acme.co')).toBe(false)
+    expect(isFreeEmailDomain('jane@sim.ai')).toBe(false)
+  })
+
+  it('is case-insensitive on the domain', () => {
+    expect(isFreeEmailDomain('Jane@GMAIL.com')).toBe(true)
+  })
+
+  it('returns false when there is no domain', () => {
+    expect(isFreeEmailDomain('jane')).toBe(false)
+    expect(isFreeEmailDomain('')).toBe(false)
+  })
+})
diff --git a/apps/sim/lib/messaging/email/free-email.ts b/apps/sim/lib/messaging/email/free-email.ts
new file mode 100644
index 00000000000..07a2f2b5002
--- /dev/null
+++ b/apps/sim/lib/messaging/email/free-email.ts
@@ -0,0 +1,17 @@
+import freeEmailDomains from 'free-email-domains'
+
+const FREE_EMAIL_DOMAINS = new Set(freeEmailDomains)
+
+/**
+ * True when the email's domain is a known free/personal provider (Gmail, Yahoo,
+ * …) rather than a work address. Shared by the demo-request schema and form so
+ * client gating and server validation agree on what counts as a work email.
+ *
+ * Isolated in its own module (not `validation.ts`) so the sizable domain list
+ * only enters bundles that need the work-email check, not every consumer of
+ * {@link quickValidateEmail}.
+ */
+export function isFreeEmailDomain(email: string): boolean {
+  const domain = email.split('@')[1]?.toLowerCase()
+  return domain ? FREE_EMAIL_DOMAINS.has(domain) : false
+}
diff --git a/apps/sim/next.config.ts b/apps/sim/next.config.ts
index 534ff891176..fd14072bbf6 100644
--- a/apps/sim/next.config.ts
+++ b/apps/sim/next.config.ts
@@ -206,8 +206,9 @@ const nextConfig: NextConfig = {
         ],
       },
       {
-        // Exclude Vercel internal resources and static assets from strict COEP, Google Drive Picker to prevent 'refused to connect' issue
-        source: '/((?!_next|_vercel|api|favicon.ico|w/.*|workspace/.*|api/tools/drive).*)',
+        // Exclude Vercel internal resources and static assets from strict COEP, Google Drive Picker
+        // and the /demo Cal.com booking embed to prevent 'refused to connect' / slow-load issues
+        source: '/((?!_next|_vercel|api|favicon.ico|w/.*|workspace/.*|api/tools/drive|demo).*)',
         headers: [
           {
             key: 'Cross-Origin-Embedder-Policy',
@@ -220,8 +221,8 @@ const nextConfig: NextConfig = {
         ],
       },
       {
-        // For main app routes, Google Drive Picker, and Vercel resources - use permissive policies
-        source: '/(w/.*|workspace/.*|api/tools/drive|_next/.*|_vercel/.*)',
+        // For main app routes, Google Drive Picker, the /demo Cal.com embed, and Vercel resources - use permissive policies
+        source: '/(w/.*|workspace/.*|api/tools/drive|demo.*|_next/.*|_vercel/.*)',
         headers: [
           {
             key: 'Cross-Origin-Embedder-Policy',