Usually this means you’ve attempted to use a Firebase service before calling Firebase initializeapp

Firebase Hosting works out-of-the-box with Firebase services, including Cloud Functions, Authentication, Realtime Database, Cloud Firestore, and Cloud Messaging. You can build powerful microservices and web apps using these complementary Firebase services.

ML Kit comes with a set of ready-to-use APIs for common mobile use cases: recognizing text, detecting faces, identifying landmarks, scanning barcodes, labeling images, and identifying the language of text .