How We Built Invitations into Firebase Authentication with No Code

We are Minimum Viable Product (MVP) specialists. With most of the MVPs we build, we have constraints around time and resources to spend on such projects.

This is the story of the time we implemented an invitation based authentication system. We wanted users to sign up into our app using Gmail or Facebook as long as they were invited to use the product.

For faster development, we use Firebase for our database needs. Firebase , a Google product, provides a realtime database and backend as a service. One of the reasons we love firebase to build out MVPs is firebase auth. With simple configuration, Firebase auth allows you to integrate many third party social sign-in providers in to your app.

Firebase itself has no method in to restrict user access by invitation and neither the admin friendly interface to invite users. Building an admin panel to control user access would mean spending time and money that our clients did not have

The Problem Statement:

1. Build an authentication system with restricted app access to non invited users using firebase auth.
2. Build an admin endpoint where admins could invite users to the app
3. Do this in the least amount of time possible.

The Solution:

Zapier is a productivity tool to automate workflows and move data between Saas apps. Zapier is a freemium service with one zap free, where a zap means one connection between two apps.

In our case that was between Firebase database and a Google Sheets spreadsheet. vice with one zap free, where a zap means one connection between two apps, in our case that was between Firebase database and google docs sheet.

We gave our clients a Google Sheet to add list of people they want to invite any time they want. Zapier would then automatically check for updates in the Google Sheet every 15 mins and update a node in firebase accordingly. In the app, Firebase would allow a user to login. We let all users authenticate in to our Firebase instance while restricting their access to the app based on their invitation status. Invited users are allowed to continue to the app starting with profile creation,. While the rest would redirect to a page showing them that they're waitlisted.

In the future we'll write out a Firebase Cloud Function to send an email out to a newly invited email from Google Sheets.

This method of quick invite creations has become a regular arrow in our quiver of tricks to build world class MVPs with an invite based login.