I’ve been working on this simple Firebase Authentication tutorial using Express JS. However, I keep encountering the following error when I try to use POSTMAN to send an API post to register the username and password. There are no coding errors, just this authentication error.

Error creating user: FirebaseAuthError: Credential implementation provided to initializeApp() via the “credential” property has insufficient permission to access the requested resource. See https://firebase.google.com/docs/admin/setup for details on how to authenticate this SDK with appropriate permissions.

Here are the roles I have assigned to my IAM Principle in my project.

• Create Service Accounts

• Firebase Admin SDK Administrator Service Agent

• Firebase Authentication Admin

• Firestore Service Agent

• Service Account Token Creator

const express = require("express");
const session = require("express-session");
const admin = require("firebase-admin");
const serviceAccount = require("./serviceAccountKey.json"); // Replace with your key

admin.initializeApp({
  credential: admin.credential.cert(serviceAccount),
  databaseURL: 'https://firebase-auth-express.firebaseio.com'
});

const app = express();
//const app = initializeApp();
const port = process.env.PORT || 3000;

app.use(express.json());
app.use(
  session({
    secret: "super-secret-key",
    resave: true,
    saveUninitialized: true,
  })
);

// Middleware to check if the user is authenticated
const checkAuth = (req, res, next) => {
  if (req.session.user) {
    next();
  } else {
    res.status(401).send("Unauthorized");
  }
};

app.get("/", (req, res) => {
  res.send(
    "Welcome to the Firebase Authentication and Post Management Example!"
  );
});

// Register new user
app.post("/register", (req, res) => {
  const { email, password } = req.body;
  admin
    .auth()
    .createUser({
      email,
      password,
    })
    .then((userRecord) => {
      console.log("Successfully created user:", userRecord.uid);
      res.send("User registered successfully");
    })
    .catch((error) => {
      console.error("Error creating user:", error);
      res.status(500).send("User registration failed");
    });
});

// Log in a user
app.post("/login", (req, res) => {
  const { email, password } = req.body;
  admin
    .auth()
    .getUserByEmail(email)
    .then((userRecord) => {
      // Check the provided password against the user's stored password hash
      // This part may vary depending on your application
      if (password === "admin123") {
        req.session.user = userRecord.uid;
        res.send("Login successful");
      } else {
        res.status(401).send("Login failed");
      }
    })
    .catch((error) => {
      console.error("Error getting user:", error);
      res.status(401).send("Login failed");
    });
});

// Log out a user
app.get("/logout", (req, res) => {
  req.session.user = null;
  res.send("Logged out");
});

// Create a post (requires authentication)
app.post("/posts", checkAuth, (req, res) => {
  const { title, content } = req.body;
  // Add logic to save the post, e.g., in a database
  res.send("Post created");
});

// Get all posts (requires authentication)
app.get("/posts", checkAuth, (req, res) => {
  // Add logic to retrieve all posts, e.g., from a database
  const posts = [
    { title: "Post 1", content: "Content of Post 1" },
    { title: "Post 2", content: "Content of Post 2" },
  ];
  res.json(posts);
});

app.listen(port, () => {
  console.log(`Server is running on port ${port}`);
});

I was expecting to recieve a message from the console.log that the user has been successfully created. And a response from the server that User registered successfully.