How to fix auth/invalid-creation-time: Creation time must be valid UTC date string in Firebase

FirebaseINTERMEDIATEMEDIUM

This Firebase Authentication error occurs when you attempt to create or update a user with an invalid creation time timestamp.

What this error means

The error indicates your application is trying to set a user's creationTime field with a value that doesn't conform to Firebase's required UTC date format.

Typical symptoms

Firebase Admin SDK throws error when calling createUser() or updateUser()
User migration scripts fail with timestamp validation errors

Common causes

Providing a non-UTC timestamp string
Using local time format instead of UTC

How to fix "auth/invalid-creation-time: Creation time must be valid UTC date string"

1Verify timestamp format

Use ISO 8601 UTC format ending with "Z".

2Convert timestamps

Convert existing timestamps to proper UTC format.

Advanced notes

Firebase requires UTC timestamps in ISO 8601 format.

Related errors

Official resources & further reading

📚Firebase Official Documentation
📖
Firebase Admin SDK - Create a User(Official Docs)