Build error: Service account object must contain a string "project_id" property

[RachelHow]

Hi @leerob! I love your React 2025 course 👍

Just a tiny issue that I ran into and failed to find solutions online. I tried deploying my code to Vercel and during build time, this is the error:

type: 'FirebaseAppError',
errorInfo: {
  code: 'app/invalid-credential',
  message: 'Service account object must contain a string "project_id" property.'
},

In my firebase.js and firebase-admin.js, I have set the projectId and project_id respectively.
I have also included the environment variables in .env, .env.local and Vercel environment variable settings.

[leerob]

Are those values set to environment variables? If so, you'll need to ensure you add the environment variables inside your Vercel project as well – for both the preview and production environments.

[RachelHow]

Hi @leerob , yes they are set to env settings in Vercel project :) On production, preview and development environments.

[leerob]

Does yours look like this?

• https://github.com/leerob/fastfeedback/blob/master/lib/firebase.js#L10
• https://github.com/leerob/fastfeedback/blob/master/lib/firebase-admin.js#L8

Is it prefixed with NEXT_PUBLIC_?

[RachelHow]

Hey @leerob, I replaced all the API keys on Vercel again to make sure there's no mistake.

After that, I ran into an error: Error: Failed to parse private key: Error: Invalid PEM formatted message.
To fix it, I added this to firebase-admin.js:
private_key: process.env.FIREBASE_PRIVATE_KEY.replace(/\\n/g, '\n'),

And it's solved! Thank you so much. 👍