What is a Backend, and why your app needs one.
A backend is the part of your app that runs on a server, not in the visitor's browser, and it is where anything private, permanent, or shared happens. If your app only shows things, it does not need one. If it saves something, checks who someone is, charges a card, or sends an email, it does.
The short version:
The frontend is what people see and click. The backend is what the app does behind it.
Anything that has to be private, saved, or shared between users needs a backend.
A backend is a set of small programs that wait for a request and answer it. On Floot, your assistant writes the backend when you describe the app. There is nothing to set up.
On other builders, "backend" often means a second account with a second bill. The rest of this guide covers the difference between frontend and backend, what a backend actually does, when you can skip one, and what each tool makes you do.
Frontend and backend, in one picture
Think of a restaurant. The dining room is the frontend: the menu, the tables, what the customer touches. The kitchen is the backend: where the food is made, where the ingredients are kept, and where customers are not allowed.
A customer never walks into the kitchen. They ask the waiter, the waiter takes the request back, and something comes out. That waiter is a request, and the kitchen is your backend.
The reason the split exists is trust. Everything in the frontend gets downloaded to the visitor's computer, so they can read it. Anything secret or important has to live where they cannot.
What a backend actually does
A backend does five jobs, and every app that needs one needs at least one of them.
It stores things, by talking to the database. When someone signs up, the backend is what writes their name down. (The database is the filing cabinet, and the backend is the person who files.)
It checks who you are. Logging in is the backend confirming a password or a Google account, then deciding what that person is allowed to see.
It keeps secrets. Your Stripe key, your email key, your AI key: none of them can sit in the frontend, because anyone could copy them out of the page. The backend holds them.
It talks to other services. Charging a card, sending a receipt, and pulling in data from another tool are all done from the backend.
It runs things without anyone watching. A weekly summary email, a nightly cleanup, and a reminder the day before an appointment all happen on the backend, on a schedule.
Notice the pattern. Every one of those is something you would not want a visitor to do, see, or change directly.
Does your app need one?
Here is the quick test. Ask what happens when someone closes the tab and comes back tomorrow.
If nothing needs to be different, you can skip the backend. A landing page, a portfolio, a calculator, and a brochure site are all frontend only.
If something needs to be remembered, protected, or sent, you need one. That covers a booking app, a client portal, a tracker, a job board, a store, and anything with logins.
Most of the apps people describe to an AI need a backend, because most of them have users, and users mean saved data.
What each tool makes you do
Every AI app builder can produce a nice-looking frontend in minutes. The backend is where they differ, and it is the part beginners hit without warning.
Lovable's own materials describe building a database app and then point you to Supabase for the backend side, which means a second account, a second dashboard, and a set of keys you have to understand. Bolt takes a similar path with a third-party service. Replit runs a backend for you but bills hosting and usage on top of the AI.
The pattern is the same everywhere it goes wrong: the app looks finished, then the first thing that needs to be saved or protected sends you off to set up a separate service.
Floot builds the backend for you as part of the app. The backend is a set of small server programs called endpoints. Each one has one job: "create a booking," "list my invoices," "send the receipt." Your assistant writes them when you describe what the app should do, and Floot hosts them.
Because Floot also includes the database, logins with Google, Microsoft, and email, file storage, email sending, scheduled jobs, and live updates, the pieces a backend normally has to be wired to are already there. You never sign up for anything else.
One thing to know: a backend does not remember
This is the part that surprises people, and it is the reason the database exists.
A backend program wakes up, answers one request, and goes back to sleep. It keeps nothing between requests, so anything you want to keep has to be written to the database or to file storage.
That is why "my app forgot everything when I refreshed" is one of the most common vibe coding complaints. The information was sitting in the frontend or in memory, and it was never saved anywhere permanent.
FAQ
What is the difference between a frontend and a backend?
The frontend is everything the visitor sees and touches in their browser. The backend runs on a server and handles saving data, checking logins, keeping secrets, and talking to other services.
Does my app need a backend?
If it only displays information, no. If it saves data, has logins, takes payments, or sends emails, yes.
Does Floot have a backend?
Yes. Your assistant writes it as server endpoints when you describe the app, and Floot hosts it with the database and logins included.
Do I need to learn to code to build a backend?
No. You describe what should happen in plain English, and the assistant writes the endpoints. Reading what it built is optional and takes about ten minutes.
Is a backend the same as a database?
No. The backend is the program that does the work, and the database is where the saved information lives. Most apps need both.
Why do other builders send me to Supabase?
Because they build the frontend and expect a separate service to act as the backend and database. Floot includes both, so there is nothing to connect.