diff --git a/.changeset/fix-otp-getclientfetch-bundle-id.md b/.changeset/fix-otp-getclientfetch-bundle-id.md
new file mode 100644
index 00000000000..478f94c93b5
--- /dev/null
+++ b/.changeset/fix-otp-getclientfetch-bundle-id.md
@@ -0,0 +1,5 @@
+---
+"thirdweb": patch
+---
+
+Fix: in-app wallet email/phone OTP login (`sendOtp`/`verifyOtp`) now routes through `getClientFetch` instead of the global `fetch`. Previously these calls never attached the SDK's platform headers, so on React Native the `x-bundle-id` header was never sent — making it impossible to use email/phone OTP login with a Bundle ID access restriction configured on the client ID, since the backend rejects requests missing that header with a 401.
diff --git a/packages/thirdweb/src/wallets/in-app/web/lib/auth/otp.test.ts b/packages/thirdweb/src/wallets/in-app/web/lib/auth/otp.test.ts
new file mode 100644
index 00000000000..b0478ddd4f5
--- /dev/null
+++ b/packages/thirdweb/src/wallets/in-app/web/lib/auth/otp.test.ts
@@ -0,0 +1,82 @@
+import { describe, expect, it, vi } from "vitest";
+import { TEST_CLIENT } from "~test/test-clients.js";
+import { getClientFetch } from "../../../../../utils/fetch.js";
+import { sendOtp, verifyOtp } from "./otp.js";
+
+vi.mock("../../../../../utils/fetch.js");
+
+describe("sendOtp", () => {
+  it("should route the request through getClientFetch so platform headers (x-bundle-id) are attached", async () => {
+    const mockFetch = vi.fn().mockResolvedValue({
+      json: () => Promise.resolve({}),
+      ok: true,
+    });
+    vi.mocked(getClientFetch).mockReturnValue(mockFetch);
+
+    await sendOtp({
+      client: TEST_CLIENT,
+      email: "user@example.com",
+      strategy: "email",
+    });
+
+    expect(getClientFetch).toHaveBeenCalledWith(TEST_CLIENT, undefined);
+    expect(mockFetch).toHaveBeenCalled();
+  });
+
+  it("should forward the ecosystem to getClientFetch so ecosystem headers are attached", async () => {
+    const mockFetch = vi.fn().mockResolvedValue({
+      json: () => Promise.resolve({}),
+      ok: true,
+    });
+    vi.mocked(getClientFetch).mockReturnValue(mockFetch);
+
+    const ecosystem = { id: "ecosystem.test" as const, partnerId: "partner-1" };
+    await sendOtp({
+      client: TEST_CLIENT,
+      ecosystem,
+      email: "user@example.com",
+      strategy: "email",
+    });
+
+    expect(getClientFetch).toHaveBeenCalledWith(TEST_CLIENT, ecosystem);
+  });
+});
+
+describe("verifyOtp", () => {
+  it("should route the request through getClientFetch so platform headers (x-bundle-id) are attached", async () => {
+    const mockFetch = vi.fn().mockResolvedValue({
+      json: () => Promise.resolve({}),
+      ok: true,
+    });
+    vi.mocked(getClientFetch).mockReturnValue(mockFetch);
+
+    await verifyOtp({
+      client: TEST_CLIENT,
+      email: "user@example.com",
+      strategy: "email",
+      verificationCode: "123456",
+    });
+
+    expect(getClientFetch).toHaveBeenCalledWith(TEST_CLIENT, undefined);
+    expect(mockFetch).toHaveBeenCalled();
+  });
+
+  it("should forward the ecosystem to getClientFetch so ecosystem headers are attached", async () => {
+    const mockFetch = vi.fn().mockResolvedValue({
+      json: () => Promise.resolve({}),
+      ok: true,
+    });
+    vi.mocked(getClientFetch).mockReturnValue(mockFetch);
+
+    const ecosystem = { id: "ecosystem.test" as const, partnerId: "partner-1" };
+    await verifyOtp({
+      client: TEST_CLIENT,
+      ecosystem,
+      email: "user@example.com",
+      strategy: "email",
+      verificationCode: "123456",
+    });
+
+    expect(getClientFetch).toHaveBeenCalledWith(TEST_CLIENT, ecosystem);
+  });
+});
diff --git a/packages/thirdweb/src/wallets/in-app/web/lib/auth/otp.ts b/packages/thirdweb/src/wallets/in-app/web/lib/auth/otp.ts
index 7a12a2fb49b..58f701526fe 100644
--- a/packages/thirdweb/src/wallets/in-app/web/lib/auth/otp.ts
+++ b/packages/thirdweb/src/wallets/in-app/web/lib/auth/otp.ts
@@ -1,4 +1,5 @@
 import type { ThirdwebClient } from "../../../../../client/client.js";
+import { getClientFetch } from "../../../../../utils/fetch.js";
 import { stringify } from "../../../../../utils/json.js";
 import {
   getLoginCallbackUrl,
@@ -20,17 +21,8 @@ export const sendOtp = async (args: PreAuthArgsType): Promise<void> => {
 
   const headers: Record<string, string> = {
     "Content-Type": "application/json",
-    "x-client-id": client.clientId,
   };
 
-  if (ecosystem?.id) {
-    headers["x-ecosystem-id"] = ecosystem.id;
-  }
-
-  if (ecosystem?.partnerId) {
-    headers["x-ecosystem-partner-id"] = ecosystem.partnerId;
-  }
-
   const body = (() => {
     switch (args.strategy) {
       case "email":
@@ -44,7 +36,7 @@ export const sendOtp = async (args: PreAuthArgsType): Promise<void> => {
     }
   })();
 
-  const response = await fetch(url, {
+  const response = await getClientFetch(client, ecosystem)(url, {
     body: stringify(body),
     headers,
     method: "POST",
@@ -85,17 +77,8 @@ export const verifyOtp = async (
 
   const headers: Record<string, string> = {
     "Content-Type": "application/json",
-    "x-client-id": client.clientId,
   };
 
-  if (ecosystem?.id) {
-    headers["x-ecosystem-id"] = ecosystem.id;
-  }
-
-  if (ecosystem?.partnerId) {
-    headers["x-ecosystem-partner-id"] = ecosystem.partnerId;
-  }
-
   const body = (() => {
     switch (args.strategy) {
       case "email":
@@ -111,7 +94,7 @@ export const verifyOtp = async (
     }
   })();
 
-  const response = await fetch(url, {
+  const response = await getClientFetch(client, ecosystem)(url, {
     body: stringify(body),
     headers,
     method: "POST",