The shortest possible tutorial. Context You have built a webapp for your startup using .Specifically, you’re taking advantage of their service to sign up and log in your users.You’re obviously using Slack, because nobody takes emojis more seriously than these guys. ⚡ Firebase for the backend Authentication User Story As a member of my beloved Startup, .It will boost my motivation and as a result I will treat my dog 🐶 better. I want to be notified when a new user signs up 1. Be Notified How to receive something in Slack? → ! Incoming WebHooks Go to Slack and click on Apps & integrations Select Build Create your by choosing a name and your team App Friennnnnnd Select and activate the functionality Incoming Webhooks Create a and select the you want to post to Webhook channel Copy the given sample curl request Paste it in your terminal Press enter BOOM Voilà ! A POST request to an url and we have a notification in our Slack. 💫💫💫 #SORTED 2. Listen to new signups Hello ! Cloud Functions Go to your and select the section Firebase console Functions Install firebase-tools if you have to Go to an empty folder in your and type: terminal firebase init Select the feature and your you want to deploy to Functions Firebase project space bar to toggle Open the folder in an editor Atom for me Add the function that listens to onCreate events (from the ) and posts a json payload to your Firebase documentation Slack hook url: That’s the step connecting the Cloud Functions to your Slack incoming Webhooks! 11 lines of code chéri You notice the use of the request library, so add it to your package.json by typing: npm i request --save One last thing to do is to deploy the to Firebase. Type the following: function firebase deploy --only functions You can go back to your section and check that it has been uploaded. Firebase Functions 3. Demo! 🥁🥁🥁🥁🥁🥁 Try and create a new user on Firebase, you should then see on your Slack something like: <a href="https://medium.com/media/f8c1f75e778d04fd926d11dc2430c48d/href">https://medium.com/media/f8c1f75e778d04fd926d11dc2430c48d/href</a> Summary You created an app on Slack and activated the I_ncoming Webhook_ feature to get an url you can post your messages to. You created a on Firebase that listens to new signup and posts to your a json payload including the email of the new user. Cloud Function Webhook url Your user story is satisfied and it’s worth mentioning that ! you didn’t have to touch your code base at all Short & Sweet 😎 PS: You probably heard scary things about Firebase billing recently but it should be all good from now on .