Once you sign up with any of those servers make sure to verify your account Email and Billing as well, Without billing verification, we aren't able to create or use their machine.
We use image kit for all our image storage for products. We use this tool as it optimizes images on runtime so we can get the different sizes of images we need on an app or website from the same source image easily. It automatically optimizes all the images as well.
Once you purchase OTP you may need to share details like where you going to use OTP then they authorize your account to send OTP to customers.
You need to keep all information correct otherwise they will not approve your account so be careful once you create an account and in some cases, once your signup they may ask to support their contact with basic information so you can send them a manual approval.
We send push notifications to customers with each product status update or you can use this to send messages to all customers from our CMS. You need to sign up and get their key to use in our system.
If you want we share our developer account and you can add in your firebase account as admin if you have an issue sharing your main Email/password. **
We used MongoDB as a database to store the information for this food ordering system. You can install MongoDB locally on the machine and used this our you can get any Cloud-hosted MongoDB to use as well. In Demo, We are using Cloud hosted MongoDB. You can create an account for basic uses for this cloud-hosted MongoDB FREE.
For further description and steps about creating free MongoDB. see here
Google API Key
We used the Google location API key to detect user locations and distances. Get Google API Key
GOOGLE PLAY STORE ACCOUNT (ANDROID)
You need to get a Google Play developer account to publish your app on the android store. Google will charge you 25 USD One time cost to upload your app. You can create an account with your existing Gmail account.
APP STORE ACCOUNT (IOS)
You need to have a developer account to upload any IOS app to the Apple store. You need to Enroll through this link. Apple will charge you 99 USD/Yearly for a personal account and they have a different price if you want to register a company.