diff --git a/apps/web/app/subscribe/celebrate/AccessStatus.test.tsx b/apps/web/app/subscribe/celebrate/AccessStatus.test.tsx
new file mode 100644
index 00000000..e23f658e
--- /dev/null
+++ b/apps/web/app/subscribe/celebrate/AccessStatus.test.tsx
@@ -0,0 +1,71 @@
+/** @vitest-environment jsdom */
+import type { ReactNode } from "react";
+import { render, screen } from "@testing-library/react";
+import { afterEach, describe, expect, it, vi } from "vitest";
+
+vi.mock("@/components/confetti-burst", () => ({
+  ConfettiBurst: () => null,
+}));
+
+vi.mock("@/components/discord-button", () => ({
+  DiscordButton: ({ children, href }: { children: ReactNode; href: string }) => (
+    <a href={href}>{children}</a>
+  ),
+}));
+
+vi.mock("./access-status-helpers", () => ({
+  STATUS_POLL_MS: 8_000,
+  STATUS_MAX_ATTEMPTS: 0,
+  formatDate: () => null,
+  derivePhase: () => "loading",
+  deriveMessage: () => "Checking access...",
+  shouldContinuePolling: () => true,
+  PHASE_ICON: {
+    loading: "o",
+    syncing: "o",
+    success: "ok",
+    warning: "!",
+    error: "x",
+  },
+  PHASE_BANNER_CLASS: {
+    loading: "",
+    syncing: "",
+    success: " success",
+    warning: " warning",
+    error: " error",
+  },
+}));
+
+import { AccessStatus } from "./AccessStatus";
+
+describe("AccessStatus", () => {
+  afterEach(() => {
+    vi.unstubAllGlobals();
+    vi.restoreAllMocks();
+    sessionStorage.clear();
+  });
+
+  it("renders the slow-processing note without a literal HTML entity", async () => {
+    vi.stubGlobal(
+      "fetch",
+      vi.fn().mockResolvedValue({
+        ok: true,
+        json: async () => ({
+          ok: true,
+          grant: null,
+          roleSync: null,
+          sandbox: { isSandbox: false },
+        }),
+      }),
+    );
+
+    render(<AccessStatus guildId="guild_1" isFresh={false} />);
+
+    expect(
+      await screen.findByText(
+        /payment is confirmed - you can safely close this page and check back later\./,
+      ),
+    ).toBeInTheDocument();
+    expect(screen.queryByText(/&mdash;/)).not.toBeInTheDocument();
+  });
+});
diff --git a/apps/web/app/subscribe/celebrate/AccessStatus.tsx b/apps/web/app/subscribe/celebrate/AccessStatus.tsx
index 4f8b759b..efc7ef74 100644
--- a/apps/web/app/subscribe/celebrate/AccessStatus.tsx
+++ b/apps/web/app/subscribe/celebrate/AccessStatus.tsx
@@ -15,6 +15,7 @@ import {
   PHASE_ICON,
   PHASE_BANNER_CLASS,
 } from "./access-status-helpers";
+import { getSandboxCelebrateNotice, shouldShowSandboxCelebrateNote } from "./sandboxSummary";
 
 /** Scoped per-tier so separate checkouts each get their own celebration. */
 const CELEBRATE_KEY_PREFIX = "celebrate_fresh_consumed:";
@@ -95,6 +96,8 @@ export function AccessStatus({
   const phase = derivePhase(data, error);
   const message = deriveMessage(data, error, phase);
   const grantDate = formatDate(data?.grant?.validThrough ?? null);
+  const sandboxNotice = getSandboxCelebrateNotice(data);
+  const shouldShowSandboxSuccessNote = shouldShowSandboxCelebrateNote(data, phase);
 
   /* Don't let transient errors halt polling — loadStatus() clears error on
      the next successful response, so we keep polling through failures. */
@@ -186,13 +189,33 @@ export function AccessStatus({
 
         {/* Failure guidance */}
         {phase === "warning" &&
-          roleSyncStatus === "failed" &&
+          (roleSyncStatus === "failed" ||
+            roleSyncStatus === "pending" ||
+            roleSyncStatus === "in_progress") &&
           data?.grant?.status !== "past_due" && (
-            <p className="text-xs text-muted-foreground">
-              We&apos;ll automatically retry syncing your Discord role. If this persists, contact
-              the server administrator.
-            </p>
+            <div className="space-y-2">
+              <p className="text-xs text-muted-foreground">
+                {roleSyncStatus === "failed"
+                  ? "We'll automatically retry syncing your Discord role. If this persists, contact the server administrator."
+                  : "Your entitlement is active, and Discord role sync is still processing in the background."}
+              </p>
+              {roleSyncStatus === "failed" && data?.roleSync?.lastError && (
+                <p className="text-xs text-muted-foreground">
+                  Current issue: {data.roleSync.lastError}
+                </p>
+              )}
+              {shouldShowSandboxSuccessNote && sandboxNotice && (
+                <p className="text-xs text-muted-foreground" data-testid="sandbox-success-note">
+                  {sandboxNotice}
+                </p>
+              )}
+            </div>
           )}
+        {phase === "success" && shouldShowSandboxSuccessNote && sandboxNotice && (
+          <p className="text-xs text-muted-foreground" data-testid="sandbox-success-note">
+            {sandboxNotice}
+          </p>
+        )}
         {phase === "warning" && data?.grant?.status === "past_due" && (
           <p className="text-xs text-muted-foreground">
             Your payment method may need updating. Please check your billing details.
@@ -201,7 +224,7 @@ export function AccessStatus({
         {pollExhausted && phase !== "warning" && phase !== "error" && (
           <p className="text-xs text-muted-foreground">
             This is taking longer than usual. Your access will be activated automatically once
-            payment is confirmed &mdash; you can safely close this page and check back later.
+            payment is confirmed - you can safely close this page and check back later.
           </p>
         )}
       </div>
diff --git a/apps/web/app/subscribe/celebrate/access-status-helpers.ts b/apps/web/app/subscribe/celebrate/access-status-helpers.ts
index 663db461..4f083c17 100644
--- a/apps/web/app/subscribe/celebrate/access-status-helpers.ts
+++ b/apps/web/app/subscribe/celebrate/access-status-helpers.ts
@@ -12,6 +12,11 @@ export type StatusResponse = {
   ok: true;
   discordUserId: string;
   discordGuildId: string;
+  sandbox: {
+    isSandbox: boolean;
+    provider: "stripe" | "authorize_net" | "nmi" | null;
+    providerLabel: string | null;
+  };
   tier: {
     id: string;
     slug: string;
@@ -65,6 +70,12 @@ export function derivePhase(data: StatusResponse | null, error: string | null):
   const roleStatus = data.roleSync?.status ?? null;
 
   if (grantStatus === "active") {
+    if (
+      data.sandbox.isSandbox &&
+      (roleStatus === "pending" || roleStatus === "in_progress" || roleStatus === "failed")
+    ) {
+      return "warning";
+    }
     if (roleStatus === "pending" || roleStatus === "in_progress") return "syncing";
     if (roleStatus === "failed") return "warning";
     return "success";
@@ -94,10 +105,14 @@ export function deriveMessage(
         ? "Syncing your Discord role..."
         : "Processing...";
     case "success":
-      return "Access active";
+      return data.sandbox.isSandbox ? "Access active in sandbox" : "Access active";
     case "warning":
       if (data.grant.status === "past_due") return "Payment needs attention";
-      return "Role sync issue \u2014 we'll retry automatically";
+      return data.sandbox.isSandbox
+        ? roleStatus === "pending" || roleStatus === "in_progress"
+          ? "Sandbox access active \u2014 role sync is still pending"
+          : "Sandbox access active \u2014 role sync still needs attention"
+        : "Role sync issue \u2014 we'll retry automatically";
     case "error":
       if (data.grant.status === "suspended_dispute") return "Access paused due to a dispute";
       return "Access inactive";
diff --git a/apps/web/app/subscribe/celebrate/sandboxSummary.test.ts b/apps/web/app/subscribe/celebrate/sandboxSummary.test.ts
new file mode 100644
index 00000000..a7ca052c
--- /dev/null
+++ b/apps/web/app/subscribe/celebrate/sandboxSummary.test.ts
@@ -0,0 +1,113 @@
+import { describe, expect, it } from "vitest";
+import { getSandboxCelebrateNotice, shouldShowSandboxCelebrateNote } from "./sandboxSummary";
+import type { StatusResponse } from "./access-status-helpers";
+
+const makeStatus = (overrides: Partial<StatusResponse> = {}): StatusResponse => ({
+  ok: true,
+  discordUserId: "user_1",
+  discordGuildId: "guild_1",
+  sandbox: {
+    isSandbox: true,
+    provider: "authorize_net",
+    providerLabel: "Authorize.Net",
+  },
+  tier: {
+    id: "tier_1",
+    slug: "starter",
+    name: "Starter",
+    displayPrice: "$5 / month",
+  },
+  grant: {
+    id: "grant_1",
+    status: "active",
+    validFrom: 1,
+    validThrough: null,
+    source: "authorize_net_subscription",
+    updatedAt: 2,
+  },
+  roleSync: {
+    id: "sync_1",
+    status: "failed",
+    requestedAt: 1,
+    updatedAt: 2,
+    lastError: "Missing role permissions",
+  },
+  ...overrides,
+});
+
+describe("sandbox celebrate summary", () => {
+  it("returns additive sandbox copy for sandbox grant results", () => {
+    expect(getSandboxCelebrateNotice(makeStatus())).toBe(
+      "Authorize.Net sandbox is active. Your entitlement succeeded for testing, and no real payment occurred.",
+    );
+  });
+
+  it("shows sandbox note for success-with-warning role sync failures", () => {
+    expect(shouldShowSandboxCelebrateNote(makeStatus(), "warning")).toBe(true);
+  });
+
+  it("shows sandbox note while sandbox role sync is still pending", () => {
+    expect(
+      shouldShowSandboxCelebrateNote(
+        makeStatus({
+          roleSync: {
+            id: "sync_3",
+            status: "pending",
+            requestedAt: 1,
+            updatedAt: 2,
+            lastError: null,
+          },
+        }),
+        "warning",
+      ),
+    ).toBe(true);
+  });
+
+  it("shows sandbox note for full success", () => {
+    expect(
+      shouldShowSandboxCelebrateNote(
+        makeStatus({
+          roleSync: {
+            id: "sync_2",
+            status: "completed",
+            requestedAt: 1,
+            updatedAt: 2,
+            lastError: null,
+          },
+        }),
+        "success",
+      ),
+    ).toBe(true);
+  });
+
+  it("does not show sandbox note outside sandbox or for billing warnings", () => {
+    expect(
+      shouldShowSandboxCelebrateNote(
+        makeStatus({
+          sandbox: {
+            isSandbox: false,
+            provider: null,
+            providerLabel: null,
+          },
+        }),
+        "warning",
+      ),
+    ).toBe(false);
+
+    expect(
+      shouldShowSandboxCelebrateNote(
+        makeStatus({
+          grant: {
+            id: "grant_2",
+            status: "past_due",
+            validFrom: 1,
+            validThrough: null,
+            source: "authorize_net_subscription",
+            updatedAt: 2,
+          },
+        }),
+        "warning",
+      ),
+    ).toBe(false);
+  });
+});
diff --git a/apps/web/app/subscribe/celebrate/sandboxSummary.ts b/apps/web/app/subscribe/celebrate/sandboxSummary.ts
new file mode 100644
index 00000000..173b1195
--- /dev/null
+++ b/apps/web/app/subscribe/celebrate/sandboxSummary.ts
@@ -0,0 +1,33 @@
+import { formatCelebrateSandboxNotice } from "@/lib/subscribeSandbox";
+import type { StatusResponse } from "./access-status-helpers";
+
+export function getSandboxCelebrateNotice(data: StatusResponse | null): string | null {
+  if (!data?.sandbox.isSandbox || !data.sandbox.provider || !data.sandbox.providerLabel) {
+    return null;
+  }
+
+  return formatCelebrateSandboxNotice({
+    isSandbox: true,
+    provider: data.sandbox.provider,
+    providerLabel: data.sandbox.providerLabel,
+  });
+}
+
+export function shouldShowSandboxCelebrateNote(
+  data: StatusResponse | null,
+  phase: string,
+): boolean {
+  if (!data?.sandbox.isSandbox || !data.grant) {
+    return false;
+  }
+
+  if (data.grant.status === "past_due") {
+    return false;
+  }
+
+  if (phase === "success" || phase === "warning") {
+    return true;
+  }
+
+  return false;
+}
diff --git a/apps/web/app/subscribe/pay/CombinedCheckout.test.tsx b/apps/web/app/subscribe/pay/CombinedCheckout.test.tsx
index 19fb4e74..57af7b1d 100644
--- a/apps/web/app/subscribe/pay/CombinedCheckout.test.tsx
+++ b/apps/web/app/subscribe/pay/CombinedCheckout.test.tsx
@@ -9,6 +9,12 @@ const baseMethods = (overrides: Partial<PaymentMethodsResolved> = {}): PaymentMe
   showStripe: false,
   showAuthorizeNet: false,
   showNmi: false,
+  sandboxContext: null,
+  sandboxContexts: {
+    authorizeNet: null,
+    stripe: null,
+    nmi: null,
+  },
   stripeLabel: "Pay",
   authorizeNetConfig: {
     amount: "5.00",
@@ -204,4 +210,80 @@ describe("CombinedCheckout age confirmation", () => {
     expect(requestInit.body).toContain('"fullName":"Ada Lovelace"');
     expect(requestInit.body).not.toContain("ageConfirmed");
   });
+
+  it("shows sandbox checkout notice when sandbox context is provided", () => {
+    renderCheckout({
+      methods: baseMethods({
+        showAuthorizeNet: true,
+        authorizeNetApiLoginId: "login",
+        authorizeNetClientKey: "client",
+        sandboxContext: {
+          isSandbox: true,
+          provider: "authorize_net",
+          providerLabel: "Authorize.Net",
+        },
+        sandboxContexts: {
+          authorizeNet: {
+            isSandbox: true,
+            provider: "authorize_net",
+            providerLabel: "Authorize.Net",
+          },
+          stripe: null,
+          nmi: null,
+        },
+      }),
+      minimumAgeYears: null,
+    });
+
+    expect(screen.getByTestId("sandbox-checkout-notice-inline")).toHaveTextContent(
+      "Authorize.Net sandbox is active for this checkout. No real payment will occur.",
+    );
+    expect(
+      screen.getAllByText(
+        "Authorize.Net sandbox is active for this checkout. No real payment will occur.",
+      ),
+    ).toHaveLength(1);
+    const cardSection = screen
+      .getByRole("heading", { name: "Credit / Debit Card" })
+      .closest(".payment-card") as HTMLElement;
+    expect(
+      within(cardSection).queryByText(/Authorize\.Net sandbox is active for this checkout/),
+    ).not.toBeInTheDocument();
+  });
+
+  it("keeps the sandbox notice scoped to the sandbox method when live Stripe is also visible", () => {
+    renderCheckout({
+      methods: baseMethods({
+        showAuthorizeNet: true,
+        showStripe: true,
+        authorizeNetApiLoginId: "login",
+        authorizeNetClientKey: "client",
+        sandboxContext: null,
+        sandboxContexts: {
+          authorizeNet: {
+            isSandbox: true,
+            provider: "authorize_net",
+            providerLabel: "Authorize.Net",
+          },
+          stripe: null,
+          nmi: null,
+        },
+      }),
+      minimumAgeYears: null,
+    });
+
+    expect(screen.queryByTestId("sandbox-checkout-notice-inline")).not.toBeInTheDocument();
+
+    const cardSection = screen
+      .getByRole("heading", { name: "Credit / Debit Card" })
+      .closest(".payment-card") as HTMLElement;
+    const stripeSection = screen
+      .getByRole("heading", { name: "Stripe" })
+      .closest(".payment-card") as HTMLElement;
+
+    expect(
+      within(cardSection).getByText(/Authorize\.Net sandbox is active for this checkout/),
+    ).toBeInTheDocument();
+    expect(within(stripeSection).queryByText(/No real payment will occur/)).not.toBeInTheDocument();
+  });
 });
diff --git a/apps/web/app/subscribe/pay/CombinedCheckout.tsx b/apps/web/app/subscribe/pay/CombinedCheckout.tsx
index 17f7169a..65da130e 100644
--- a/apps/web/app/subscribe/pay/CombinedCheckout.tsx
+++ b/apps/web/app/subscribe/pay/CombinedCheckout.tsx
@@ -2,6 +2,7 @@
 
 import { useState } from "react";
 import { formatAgeConfirmationError } from "@/lib/ageRequirement";
+import { formatCheckoutSandboxNotice } from "@/lib/subscribeSandbox";
 import { AgeConfirmationField } from "./AgeConfirmationField";
 import { AuthorizeNetCard } from "./AuthorizeNetCard";
 import type { PaymentMethodsResolved } from "./helpers";
@@ -116,6 +117,16 @@ export function CombinedCheckout({
   const canClaimFree = methods.isFree && isActive;
   // Free-claim takes precedence — never show paid forms for a free tier.
   const canCheckout = hasPaymentMethods && isActive && !canClaimFree;
+  const authorizeNetSandboxNotice = methods.sandboxContexts.authorizeNet
+    ? formatCheckoutSandboxNotice(methods.sandboxContexts.authorizeNet)
+    : null;
+  const stripeSandboxNotice = methods.sandboxContexts.stripe
+    ? formatCheckoutSandboxNotice(methods.sandboxContexts.stripe)
+    : null;
+  const nmiSandboxNotice = methods.sandboxContexts.nmi
+    ? formatCheckoutSandboxNotice(methods.sandboxContexts.nmi)
+    : null;
+  const shouldRenderPerMethodSandboxNotices = methods.sandboxContext === null;
 
   return (
     <>
@@ -192,115 +203,131 @@ export function CombinedCheckout({
 
       {/* Payment methods */}
       {canCheckout && (
-        <div className="payment-grid">
-          {methods.showAuthorizeNet && (
-            <div className="payment-card space-y-3">
-              <h3>Credit / Debit Card</h3>
-              <AuthorizeNetCard
-                tierSlug={tierParam}
-                guildId={guildId}
-                amount={methods.authorizeNetConfig?.amount ?? null}
-                mode={methods.authorizeNetConfig?.mode ?? null}
-                intervalLabel={
-                  methods.authorizeNetConfig?.mode === "subscription"
-                    ? methods.authorizeNetConfig.intervalLabel
-                    : null
-                }
-                apiLoginId={methods.authorizeNetApiLoginId}
-                clientKey={methods.authorizeNetClientKey}
-                configError={methods.authorizeNetError}
-                environment={methods.authorizeNetEnv}
-                intakeFullName={fullName}
-                intakeEmail={email}
-                ageConfirmed={ageGateEnabled ? ageConfirmed : undefined}
-                beforeSubmitContent={renderAgeConfirmationField("card")}
-                onBeforeSubmit={
-                  anyIntake || ageGateEnabled
-                    ? () => {
-                        if (!validateAgeGate("card")) {
-                          return false;
-                        }
-                        if (anyIntake && intake) {
-                          const err = validateIntake(intake, fullName, email);
-                          if (err) {
-                            setIntakeError(err);
+        <div className="space-y-4" data-testid="checkout-shell">
+          {methods.sandboxContext && (
+            <div className="banner warning" data-testid="sandbox-checkout-notice-inline">
+              {formatCheckoutSandboxNotice(methods.sandboxContext)}
+            </div>
+          )}
+          <div className="payment-grid">
+            {methods.showAuthorizeNet && (
+              <div className="payment-card space-y-3">
+                <h3>Credit / Debit Card</h3>
+                {shouldRenderPerMethodSandboxNotices && authorizeNetSandboxNotice && (
+                  <div className="banner warning">{authorizeNetSandboxNotice}</div>
+                )}
+                <AuthorizeNetCard
+                  tierSlug={tierParam}
+                  guildId={guildId}
+                  amount={methods.authorizeNetConfig?.amount ?? null}
+                  mode={methods.authorizeNetConfig?.mode ?? null}
+                  intervalLabel={
+                    methods.authorizeNetConfig?.mode === "subscription"
+                      ? methods.authorizeNetConfig.intervalLabel
+                      : null
+                  }
+                  apiLoginId={methods.authorizeNetApiLoginId}
+                  clientKey={methods.authorizeNetClientKey}
+                  configError={methods.authorizeNetError}
+                  environment={methods.authorizeNetEnv}
+                  intakeFullName={fullName}
+                  intakeEmail={email}
+                  ageConfirmed={ageGateEnabled ? ageConfirmed : undefined}
+                  beforeSubmitContent={renderAgeConfirmationField("card")}
+                  onBeforeSubmit={
+                    anyIntake || ageGateEnabled
+                      ? () => {
+                          if (!validateAgeGate("card")) {
                             return false;
                           }
+                          if (anyIntake && intake) {
+                            const err = validateIntake(intake, fullName, email);
+                            if (err) {
+                              setIntakeError(err);
+                              return false;
+                            }
+                          }
+                          setIntakeError(null);
+                          return true;
                         }
-                        setIntakeError(null);
-                        return true;
-                      }
-                    : undefined
-                }
-              />
-            </div>
-          )}
+                      : undefined
+                  }
+                />
+              </div>
+            )}
 
-          {methods.showStripe && (
-            <div className="payment-card space-y-3">
-              <h3>Stripe</h3>
-              <form
-                action="/api/subscribe/stripe"
-                method="POST"
-                onSubmit={(e) => guardIntake(e, "stripe")}
-              >
-                <input type="hidden" name="tier" value={tierParam} />
-                <input type="hidden" name="guildId" value={guildId} />
-                <input type="hidden" name="fullName" value={fullName} />
-                <input type="hidden" name="email" value={email} />
-                {ageGateEnabled && (
-                  <input
-                    type="hidden"
-                    name="ageConfirmed"
-                    value={ageConfirmed ? "true" : "false"}
-                  />
+            {methods.showStripe && (
+              <div className="payment-card space-y-3">
+                <h3>Stripe</h3>
+                {shouldRenderPerMethodSandboxNotices && stripeSandboxNotice && (
+                  <div className="banner warning">{stripeSandboxNotice}</div>
                 )}
-                {renderAgeConfirmationField("stripe")}
-                <button className="button" type="submit">
-                  {methods.stripeLabel}
-                </button>
-              </form>
-            </div>
-          )}
+                <form
+                  action="/api/subscribe/stripe"
+                  method="POST"
+                  onSubmit={(e) => guardIntake(e, "stripe")}
+                >
+                  <input type="hidden" name="tier" value={tierParam} />
+                  <input type="hidden" name="guildId" value={guildId} />
+                  <input type="hidden" name="fullName" value={fullName} />
+                  <input type="hidden" name="email" value={email} />
+                  {ageGateEnabled && (
+                    <input
+                      type="hidden"
+                      name="ageConfirmed"
+                      value={ageConfirmed ? "true" : "false"}
+                    />
+                  )}
+                  {renderAgeConfirmationField("stripe")}
+                  <button className="button" type="submit">
+                    {methods.stripeLabel}
+                  </button>
+                </form>
+              </div>
+            )}
 
-          {methods.showNmi && (
-            <div className="payment-card space-y-3">
-              <h3>NMI</h3>
-              {renderAgeConfirmationField("nmi")}
-              <a
-                className="button"
-                href={methods.nmiConfig?.hostedUrl}
-                target="_blank"
-                rel="noreferrer"
-                onClick={async (e) => {
-                  if (!guardIntake(e, "nmi")) {
-                    e.preventDefault();
-                    return;
-                  }
-                  // Save intake before navigating to external NMI checkout
-                  if (anyIntake || ageGateEnabled) {
-                    e.preventDefault();
-                    await fetch("/api/subscribe/intake", {
-                      method: "PUT",
-                      headers: { "Content-Type": "application/json" },
-                      body: JSON.stringify({
-                        fullName,
-                        email,
-                        ...(ageGateEnabled ? { ageConfirmed } : {}),
-                      }),
-                    }).catch(() => {});
-                    window.open(
-                      methods.nmiConfig?.hostedUrl ?? "",
-                      "_blank",
-                      "noopener,noreferrer",
-                    );
-                  }
-                }}
-              >
-                Pay
-              </a>
-            </div>
-          )}
+            {methods.showNmi && (
+              <div className="payment-card space-y-3">
+                <h3>NMI</h3>
+                {shouldRenderPerMethodSandboxNotices && nmiSandboxNotice && (
+                  <div className="banner warning">{nmiSandboxNotice}</div>
+                )}
+                {renderAgeConfirmationField("nmi")}
+                <a
+                  className="button"
+                  href={methods.nmiConfig?.hostedUrl}
+                  target="_blank"
+                  rel="noreferrer"
+                  onClick={async (e) => {
+                    if (!guardIntake(e, "nmi")) {
+                      e.preventDefault();
+                      return;
+                    }
+                    // Save intake before navigating to external NMI checkout
+                    if (anyIntake || ageGateEnabled) {
+                      e.preventDefault();
+                      await fetch("/api/subscribe/intake", {
+                        method: "PUT",
+                        headers: { "Content-Type": "application/json" },
+                        body: JSON.stringify({
+                          fullName,
+                          email,
+                          ...(ageGateEnabled ? { ageConfirmed } : {}),
+                        }),
+                      }).catch(() => {});
+                      window.open(
+                        methods.nmiConfig?.hostedUrl ?? "",
+                        "_blank",
+                        "noopener,noreferrer",
+                      );
+                    }
+                  }}
+                >
+                  Pay
+                </a>
+              </div>
+            )}
+          </div>
         </div>
       )}
     </>
diff --git a/apps/web/app/subscribe/pay/helpers.ts b/apps/web/app/subscribe/pay/helpers.ts
index 3348e83b..589ec4ac 100644
--- a/apps/web/app/subscribe/pay/helpers.ts
+++ b/apps/web/app/subscribe/pay/helpers.ts
@@ -8,6 +8,14 @@ import {
   type PaymentProviderFlags,
 } from "@/lib/paymentProviders";
 import { resolveStripeCheckoutConfig } from "@/lib/stripeCheckout";
+import { optionalEnv } from "@/lib/serverEnv";
+import {
+  resolveCheckoutSandboxContext,
+  resolveCheckoutSandboxContexts,
+  type PaymentMethodSandboxContexts,
+  resolveStripeSandboxEnvironment,
+  type SandboxContext,
+} from "@/lib/subscribeSandbox";
 import { fetchTierForCheckout } from "@/lib/tierCatalog";
 import { isTierFree } from "@/lib/api/subscribe/freeClaim";
 
@@ -16,6 +24,8 @@ export type PaymentMethodsResolved = {
   showStripe: boolean;
   showAuthorizeNet: boolean;
   showNmi: boolean;
+  sandboxContext: SandboxContext | null;
+  sandboxContexts: PaymentMethodSandboxContexts;
   stripeLabel: string;
   authorizeNetConfig: {
     amount: string;
@@ -88,9 +98,9 @@ export async function resolvePaymentMethods(
     ? resolveStripeCheckoutConfig(tier)
     : { ok: false as const, error: "Stripe checkout is unavailable." };
   const stripeLabel = stripeConfigResult.ok ? "Pay" : "Stripe unavailable";
-
   const authorizeNetState = await resolveAuthorizeNetState(tier, guildId, authorizeNetEnabled);
   const nmiConfig = resolveNmiState(tier);
+  const stripeEnvironment = resolveStripeSandboxEnvironment(optionalEnv("STRIPE_SECRET_KEY"));
 
   const showStripe = stripeEnabled && Boolean(tier && stripeConfigResult.ok);
   const showAuthorizeNet =
@@ -104,12 +114,30 @@ export async function resolvePaymentMethods(
   const showNmi = nmiEnabled && Boolean(tier && nmiConfig && nmiConfig.hostedUrl);
 
   const isFree = tier ? isTierFree(tier) : false;
+  const sandboxContexts = resolveCheckoutSandboxContexts({
+    showAuthorizeNet,
+    showStripe,
+    showNmi,
+    authorizeNetEnv: authorizeNetState.env,
+    stripeEnvironment,
+    nmiSandbox: false, // NMI sandbox mode is not yet surfaced from guild config.
+  });
+  const sandboxContext = resolveCheckoutSandboxContext({
+    showAuthorizeNet,
+    showStripe,
+    showNmi,
+    authorizeNetEnv: authorizeNetState.env,
+    stripeEnvironment,
+    nmiSandbox: false, // NMI sandbox mode is not yet surfaced from guild config.
+  });
 
   return {
     isFree,
     showStripe,
     showAuthorizeNet,
     showNmi,
+    sandboxContext,
+    sandboxContexts,
     stripeLabel,
     authorizeNetConfig: authorizeNetState.config,
     authorizeNetApiLoginId: authorizeNetState.apiLoginId,
diff --git a/apps/web/e2e/visual.spec.ts b/apps/web/e2e/visual.spec.ts
index 6834f737..9fb6bcc2 100644
--- a/apps/web/e2e/visual.spec.ts
+++ b/apps/web/e2e/visual.spec.ts
@@ -511,8 +511,47 @@ test.describe("visual", () => {
       });
     }
 
+    await page.route("**/api/subscribe/status**", async (route) => {
+      await route.fulfill({
+        status: 200,
+        contentType: "application/json",
+        body: JSON.stringify({
+          ok: true,
+          discordUserId: visualFlowMemberUserId,
+          discordGuildId: seeded.discordGuildId,
+          sandbox: {
+            isSandbox: true,
+            provider: "authorize_net",
+            providerLabel: "Authorize.Net",
+          },
+          tier: {
+            id: "starter-tier",
+            slug: "starter",
+            name: "Starter",
+            displayPrice: "$5 / month",
+          },
+          grant: {
+            id: "grant_visual_starter",
+            status: "active",
+            validFrom: fixedTimestamp,
+            validThrough: null,
+            source: "authorize_net_subscription",
+            updatedAt: fixedTimestamp,
+          },
+          roleSync: {
+            id: "role_sync_visual_failed",
+            status: "failed",
+            requestedAt: fixedTimestamp,
+            updatedAt: fixedTimestamp,
+            lastError: "Bot role hierarchy is below the managed tier role.",
+          },
+        }),
+      });
+    });
+
     await page.goto(`/subscribe/celebrate?tier=starter`);
     await expect(page.getByRole("heading", { name: "Your access" })).toBeVisible();
+    await expect(page.getByTestId("sandbox-success-note")).toBeVisible();
 
     await waitForFonts(page);
     await expect(page).toHaveScreenshot("subscribe-celebrate-viewport.png");
diff --git a/apps/web/e2e/visual.spec.ts-snapshots/subscribe-celebrate-full-chromium-linux.png b/apps/web/e2e/visual.spec.ts-snapshots/subscribe-celebrate-full-chromium-linux.png
index b9e6a238..b86b2785 100644
Binary files a/apps/web/e2e/visual.spec.ts-snapshots/subscribe-celebrate-full-chromium-linux.png and b/apps/web/e2e/visual.spec.ts-snapshots/subscribe-celebrate-full-chromium-linux.png differ
diff --git a/apps/web/e2e/visual.spec.ts-snapshots/subscribe-celebrate-full-chromium-win32.png b/apps/web/e2e/visual.spec.ts-snapshots/subscribe-celebrate-full-chromium-win32.png
index 3d5ce315..0570c08b 100644
Binary files a/apps/web/e2e/visual.spec.ts-snapshots/subscribe-celebrate-full-chromium-win32.png and b/apps/web/e2e/visual.spec.ts-snapshots/subscribe-celebrate-full-chromium-win32.png differ
diff --git a/apps/web/e2e/visual.spec.ts-snapshots/subscribe-celebrate-viewport-chromium-linux.png b/apps/web/e2e/visual.spec.ts-snapshots/subscribe-celebrate-viewport-chromium-linux.png
index 5a34f59e..07233fc9 100644
Binary files a/apps/web/e2e/visual.spec.ts-snapshots/subscribe-celebrate-viewport-chromium-linux.png and b/apps/web/e2e/visual.spec.ts-snapshots/subscribe-celebrate-viewport-chromium-linux.png differ
diff --git a/apps/web/e2e/visual.spec.ts-snapshots/subscribe-celebrate-viewport-chromium-win32.png b/apps/web/e2e/visual.spec.ts-snapshots/subscribe-celebrate-viewport-chromium-win32.png
index 3ab3d793..96f4c4ef 100644
Binary files a/apps/web/e2e/visual.spec.ts-snapshots/subscribe-celebrate-viewport-chromium-win32.png and b/apps/web/e2e/visual.spec.ts-snapshots/subscribe-celebrate-viewport-chromium-win32.png differ
diff --git a/apps/web/e2e/visual.spec.ts-snapshots/subscribe-pay-age-gate-full-chromium-linux.png b/apps/web/e2e/visual.spec.ts-snapshots/subscribe-pay-age-gate-full-chromium-linux.png
index 61e1c8f1..c0fce31b 100644
Binary files a/apps/web/e2e/visual.spec.ts-snapshots/subscribe-pay-age-gate-full-chromium-linux.png and b/apps/web/e2e/visual.spec.ts-snapshots/subscribe-pay-age-gate-full-chromium-linux.png differ
diff --git a/apps/web/e2e/visual.spec.ts-snapshots/subscribe-pay-age-gate-full-chromium-win32.png b/apps/web/e2e/visual.spec.ts-snapshots/subscribe-pay-age-gate-full-chromium-win32.png
index f68331ae..2b61c529 100644
Binary files a/apps/web/e2e/visual.spec.ts-snapshots/subscribe-pay-age-gate-full-chromium-win32.png and b/apps/web/e2e/visual.spec.ts-snapshots/subscribe-pay-age-gate-full-chromium-win32.png differ
diff --git a/apps/web/e2e/visual.spec.ts-snapshots/subscribe-pay-full-chromium-linux.png b/apps/web/e2e/visual.spec.ts-snapshots/subscribe-pay-full-chromium-linux.png
index 51b23478..c0fce31b 100644
Binary files a/apps/web/e2e/visual.spec.ts-snapshots/subscribe-pay-full-chromium-linux.png and b/apps/web/e2e/visual.spec.ts-snapshots/subscribe-pay-full-chromium-linux.png differ
diff --git a/apps/web/lib/api/subscribe/status.ts b/apps/web/lib/api/subscribe/status.ts
index 3d0e8779..7445c1a1 100644
--- a/apps/web/lib/api/subscribe/status.ts
+++ b/apps/web/lib/api/subscribe/status.ts
@@ -1,4 +1,6 @@
 import type { ConvexHttpClient } from "convex/browser";
+import { optionalEnv } from "@/lib/serverEnv";
+import { buildSandboxInfo, resolveStripeSandboxEnvironment } from "@/lib/subscribeSandbox";
 
 type OwnerSession = {
   guildId: string;
@@ -174,11 +176,18 @@ export async function resolveSubscribeStatus(args: {
       : [];
 
     const roleSync = roleSyncRequests?.[0] ?? null;
+    const sandbox = buildSandboxInfo({
+      source: grant?.source ?? null,
+      authorizeNetEnv: optionalEnv("AUTHORIZE_NET_ENV") ?? null,
+      stripeEnvironment: resolveStripeSandboxEnvironment(optionalEnv("STRIPE_SECRET_KEY")),
+      nmiSandbox: false, // NMI sandbox mode is not yet surfaced from guild config.
+    });
 
     return {
       status: 200,
       body: {
         ok: true,
+        sandbox,
         accountId: ownerSession.accountId ?? null,
         discordUserId: ownerSession.discordUserId ?? null,
         discordGuildId: ownerSession.guildId,
diff --git a/apps/web/lib/subscribeSandbox.test.ts b/apps/web/lib/subscribeSandbox.test.ts
new file mode 100644
index 00000000..c72f86cb
--- /dev/null
+++ b/apps/web/lib/subscribeSandbox.test.ts
@@ -0,0 +1,123 @@
+import { describe, expect, it } from "vitest";
+import {
+  buildSandboxInfo,
+  formatCheckoutSandboxNotice,
+  resolveCheckoutSandboxContexts,
+  resolveCheckoutSandboxContext,
+  resolveGrantSandboxContext,
+} from "./subscribeSandbox";
+
+describe("subscribe sandbox helpers", () => {
+  it("detects authorize.net sandbox checkout context", () => {
+    expect(
+      resolveCheckoutSandboxContext({
+        showAuthorizeNet: true,
+        showStripe: false,
+        showNmi: false,
+        authorizeNetEnv: "sandbox",
+      }),
+    ).toEqual({
+      isSandbox: true,
+      provider: "authorize_net",
+      providerLabel: "Authorize.Net",
+    });
+  });
+
+  it("does not flag production authorize.net checkout as sandbox", () => {
+    expect(
+      resolveCheckoutSandboxContext({
+        showAuthorizeNet: true,
+        showStripe: false,
+        showNmi: false,
+        authorizeNetEnv: "production",
+      }),
+    ).toBeNull();
+  });
+
+  it("treats missing authorize.net env as production-safe", () => {
+    expect(
+      resolveCheckoutSandboxContext({
+        showAuthorizeNet: true,
+        showStripe: false,
+        showNmi: false,
+      }),
+    ).toBeNull();
+  });
+
+  it("keeps mixed checkout methods from showing a global sandbox banner", () => {
+    const contexts = resolveCheckoutSandboxContexts({
+      showAuthorizeNet: true,
+      showStripe: true,
+      showNmi: false,
+      authorizeNetEnv: "sandbox",
+      stripeEnvironment: "production",
+    });
+
+    expect(contexts).toEqual({
+      authorizeNet: {
+        isSandbox: true,
+        provider: "authorize_net",
+        providerLabel: "Authorize.Net",
+      },
+      stripe: null,
+      nmi: null,
+    });
+    expect(
+      resolveCheckoutSandboxContext({
+        showAuthorizeNet: true,
+        showStripe: true,
+        showNmi: false,
+        authorizeNetEnv: "sandbox",
+        stripeEnvironment: "production",
+      }),
+    ).toBeNull();
+  });
+
+  it("does not create a provider-specific global banner when multiple sandbox methods are visible", () => {
+    expect(
+      resolveCheckoutSandboxContext({
+        showAuthorizeNet: true,
+        showStripe: true,
+        showNmi: false,
+        authorizeNetEnv: "sandbox",
+        stripeEnvironment: "sandbox",
+      }),
+    ).toBeNull();
+  });
+
+  it("builds additive checkout copy", () => {
+    expect(
+      formatCheckoutSandboxNotice({
+        isSandbox: true,
+        provider: "authorize_net",
+        providerLabel: "Authorize.Net",
+      }),
+    ).toBe("Authorize.Net sandbox is active for this checkout. No real payment will occur.");
+  });
+
+  it("detects sandbox celebrate state from grant source", () => {
+    expect(
+      resolveGrantSandboxContext({
+        source: "authorize_net_subscription",
+        authorizeNetEnv: "sandbox",
+      }),
+    ).toEqual({
+      isSandbox: true,
+      provider: "authorize_net",
+      providerLabel: "Authorize.Net",
+    });
+  });
+
+  it("clears provider details for production grants", () => {
+    expect(
+      buildSandboxInfo({
+        source: "authorize_net_subscription",
+        authorizeNetEnv: "production",
+      }),
+    ).toEqual({
+      isSandbox: false,
+      provider: null,
+      providerLabel: null,
+    });
+  });
+});
diff --git a/apps/web/lib/subscribeSandbox.ts b/apps/web/lib/subscribeSandbox.ts
new file mode 100644
index 00000000..a0600a98
--- /dev/null
+++ b/apps/web/lib/subscribeSandbox.ts
@@ -0,0 +1,195 @@
+import {
+  detectStripeEnvironment,
+  type ProviderEnvironment,
+  type ProviderKey,
+} from "@/lib/providerEnvironment";
+
+export type SandboxContext = {
+  isSandbox: true;
+  provider: ProviderKey;
+  providerLabel: string;
+};
+
+type CheckoutSandboxInput = {
+  showAuthorizeNet: boolean;
+  showStripe: boolean;
+  showNmi: boolean;
+  authorizeNetEnv?: string | null;
+  stripeEnvironment?: ProviderEnvironment | null;
+  nmiSandbox?: boolean;
+};
+
+type GrantSandboxInput = {
+  source?: string | null;
+  authorizeNetEnv?: string | null;
+  stripeEnvironment?: ProviderEnvironment | null;
+  nmiSandbox?: boolean;
+};
+
+export type SandboxInfo = {
+  isSandbox: boolean;
+  provider: ProviderKey | null;
+  providerLabel: string | null;
+};
+
+export type PaymentMethodSandboxContexts = {
+  authorizeNet: SandboxContext | null;
+  stripe: SandboxContext | null;
+  nmi: SandboxContext | null;
+};
+
+const PROVIDER_LABELS: Record<ProviderKey, string> = {
+  stripe: "Stripe",
+  authorize_net: "Authorize.Net",
+  nmi: "NMI",
+};
+
+function normalizeEnvironment(value: string | null | undefined): "sandbox" | "production" | null {
+  const normalized = value?.trim().toLowerCase();
+  if (normalized === "sandbox" || normalized === "production") {
+    return normalized;
+  }
+  return null;
+}
+
+function resolveProviderSandboxContext(
+  provider: ProviderKey,
+  options?: {
+    authorizeNetEnv?: string | null;
+    stripeEnvironment?: ProviderEnvironment | null;
+    nmiSandbox?: boolean;
+  },
+): SandboxContext | null {
+  switch (provider) {
+    case "authorize_net": {
+      const environment = normalizeEnvironment(options?.authorizeNetEnv) ?? "production";
+      return environment === "sandbox"
+        ? {
+            isSandbox: true,
+            provider,
+            providerLabel: PROVIDER_LABELS[provider],
+          }
+        : null;
+    }
+    case "stripe": {
+      const environment = options?.stripeEnvironment ?? null;
+      return environment === "sandbox"
+        ? {
+            isSandbox: true,
+            provider,
+            providerLabel: PROVIDER_LABELS[provider],
+          }
+        : null;
+    }
+    case "nmi":
+      return options?.nmiSandbox
+        ? {
+            isSandbox: true,
+            provider,
+            providerLabel: PROVIDER_LABELS[provider],
+          }
+        : null;
+  }
+}
+
+function resolveProviderFromGrantSource(source: string | null | undefined): ProviderKey | null {
+  if (!source) {
+    return null;
+  }
+  if (source.startsWith("authorize_net_")) {
+    return "authorize_net";
+  }
+  if (source.startsWith("stripe_")) {
+    return "stripe";
+  }
+  if (source.startsWith("nmi_")) {
+    return "nmi";
+  }
+  return null;
+}
+
+export function resolveCheckoutSandboxContext(input: CheckoutSandboxInput): SandboxContext | null {
+  const contexts = resolveCheckoutSandboxContexts(input);
+  const visibleMethodCount =
+    Number(input.showAuthorizeNet) + Number(input.showStripe) + Number(input.showNmi);
+  const visibleSandboxContexts = Object.values(contexts).filter((context) => context !== null);
+
+  if (
+    visibleMethodCount !== 1 ||
+    visibleSandboxContexts.length === 0 ||
+    visibleSandboxContexts.length !== visibleMethodCount
+  ) {
+    return null;
+  }
+
+  return visibleSandboxContexts[0];
+}
+
+export function resolveCheckoutSandboxContexts(
+  input: CheckoutSandboxInput,
+): PaymentMethodSandboxContexts {
+  return {
+    authorizeNet: input.showAuthorizeNet
+      ? resolveProviderSandboxContext("authorize_net", {
+          authorizeNetEnv: input.authorizeNetEnv,
+        })
+      : null,
+    stripe: input.showStripe
+      ? resolveProviderSandboxContext("stripe", {
+          stripeEnvironment: input.stripeEnvironment,
+        })
+      : null,
+    nmi: input.showNmi
+      ? resolveProviderSandboxContext("nmi", {
+          nmiSandbox: input.nmiSandbox,
+        })
+      : null,
+  };
+}
+
+export function resolveGrantSandboxContext(input: GrantSandboxInput): SandboxContext | null {
+  const provider = resolveProviderFromGrantSource(input.source);
+  if (!provider) {
+    return null;
+  }
+  return resolveProviderSandboxContext(provider, {
+    authorizeNetEnv: input.authorizeNetEnv,
+    stripeEnvironment: input.stripeEnvironment,
+    nmiSandbox: input.nmiSandbox,
+  });
+}
+
+export function buildSandboxInfo(input: GrantSandboxInput): SandboxInfo {
+  const provider = resolveProviderFromGrantSource(input.source);
+  if (!provider) {
+    return { isSandbox: false, provider: null, providerLabel: null };
+  }
+
+  const context = resolveProviderSandboxContext(provider, {
+    authorizeNetEnv: input.authorizeNetEnv,
+    stripeEnvironment: input.stripeEnvironment,
+    nmiSandbox: input.nmiSandbox,
+  });
+
+  if (!context) {
+    return { isSandbox: false, provider: null, providerLabel: null };
+  }
+
+  return {
+    isSandbox: true,
+    provider: context.provider,
+    providerLabel: context.providerLabel,
+  };
+}
+
+export function formatCheckoutSandboxNotice(context: SandboxContext): string {
+  return `${context.providerLabel} sandbox is active for this checkout. No real payment will occur.`;
+}
+
+export function formatCelebrateSandboxNotice(context: SandboxContext): string {
+  return `${context.providerLabel} sandbox is active. Your entitlement succeeded for testing, and no real payment occurred.`;
+}
+
+export function resolveStripeSandboxEnvironment(secretKey: string | null | undefined) {
+  return detectStripeEnvironment(secretKey ?? "");
+}