diff --git a/mobile/src/lib/api/cognito-auth.ts b/mobile/src/lib/api/cognito-auth.ts
index 5bf13db..de78e3f 100644
--- a/mobile/src/lib/api/cognito-auth.ts
+++ b/mobile/src/lib/api/cognito-auth.ts
@@ -1,16 +1,6 @@
-import {
-  CognitoUserPool,
-  CognitoUser,
-  AuthenticationDetails,
-  CognitoUserSession,
-} from 'amazon-cognito-identity-js';
+import type { CognitoUserSession } from 'amazon-cognito-identity-js';
 import Config from '../../config';
 
-const userPool = new CognitoUserPool({
-  UserPoolId: Config.COGNITO_USER_POOL_ID,
-  ClientId: Config.COGNITO_CLIENT_ID,
-});
-
 export interface CognitoTokens {
   accessToken: string;
   idToken: string;
@@ -28,10 +18,22 @@ function extractTokens(session: CognitoUserSession): CognitoTokens {
   };
 }
 
-export function authenticateWithCredentials(
+export async function authenticateWithCredentials(
   email: string,
   password: string,
 ): Promise<CognitoTokens> {
+  // Lazy-load to keep amazon-cognito-identity-js out of the startup module graph
+  const {
+    CognitoUserPool,
+    CognitoUser,
+    AuthenticationDetails,
+  } = await import('amazon-cognito-identity-js');
+
+  const userPool = new CognitoUserPool({
+    UserPoolId: Config.COGNITO_USER_POOL_ID,
+    ClientId: Config.COGNITO_CLIENT_ID,
+  });
+
   return new Promise((resolve, reject) => {
     const cognitoUser = new CognitoUser({
       Username: email,