@@ -0,0 +1,5 @@
+---
+'@clerk/backend': minor
+---
+
+Add an optional `secondFactorVerification` parameter (`'fresh' | 'stale'`) to `createSignInToken()`, which lets a user with a second factor enabled complete the sign-in without being prompted for it. `expiresInSeconds` is now optional.
@@ -43,4 +43,36 @@ describe('SignInTokenAPI', () => {
 
     expect(response.id).toBe('sign_in_token_123');
   });
+
+  it('sends the second factor verification as second_factor_verification', async () => {
+    server.use(
+      http.post(
+        'https://api.clerk.test/v1/sign_in_tokens',
+        validateHeaders(async ({ request }) => {
+          const body = await request.json();
+          expect(body).toEqual({
+            user_id: 'user_123',
+            second_factor_verification: 'stale',
+          });
+
+          return HttpResponse.json({
+            id: 'sign_in_token_123',
+            user_id: 'user_123',
+            token: 'token_123',
+            status: 'pending',
+            url: 'https://accounts.example.com/tickets/token_123',
+            created_at: 1,
+            updated_at: 1,
+          });
+        }),
+      ),
+    );
+
+    const response = await apiClient.signInTokens.createSignInToken({
+      userId: 'user_123',
+      secondFactorVerification: 'stale',
+    });
+
+    expect(response.id).toBe('sign_in_token_123');
+  });
 });
@@ -8,8 +8,10 @@ export type CreateSignInTokensParams = {
   userId: string;
   /** The ID of the organization to activate when the user signs in. Organizations must be enabled for the instance, and the user must be a member of the organization. */
   orgId?: string;
-  /** The number of seconds until the sign-in token expires. By default, the duration is `2592000` (30 days). */
-  expiresInSeconds: number;
+  /** The number of seconds until the sign-in token expires. By default, the duration is `2592000` (30 days), or `600` (10 minutes) when `secondFactorVerification` is set. */
+  expiresInSeconds?: number;
+  /** Lets a user with a second factor enabled complete the sign-in without being prompted for it. With `fresh`, the second factor is treated as verified at sign-in. With `stale`, it is treated as unverified, so any reverification that requires a second factor prompts the user to complete one. Has no effect for users without a second factor enabled. */
+  secondFactorVerification?: 'fresh' | 'stale';
 };
 
 const basePath = '/sign_in_tokens';
-Original file line number
+Diff line change
@@ @@ -0,0 +1,5 @@ @@
 +---
 +'@clerk/backend': minor
 +---
++
 +Add an optional `secondFactorVerification` parameter (`'fresh' | 'stale'`) to `createSignInToken()`, which lets a user with a second factor enabled complete the sign-in without being prompted for it. `expiresInSeconds` is now optional.