Supabase Tutorial: First Table, Security & App Connection

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Supabase gives you a ready-made app backend: database, user authentication, file storage and automatic API, and you’ll have your first table serving data to your app in fifteen minutes. In this tutorial we walk through every step from empty project to data displayed in your application, including the one step you cannot skip: securing your table.

The steps follow the official Supabase guides. For what the platform is and why people building with AI choose it so often, see our Supabase guide.

Before You Start: Plan Your Data

Before you create your first table, write down what data your app stores and who can see it. For example: classes are visible to everyone, a booking is visible only to the person who made it and the instructor. That note immediately gives you the access rules you’ll enter in Row Level Security later. Planning rules after building the app usually ends with some tables left unprotected.

Step 1. Project

After creating your account, you create a new project in your organization panel. You enter a name, database password and region. Save the password immediately in your password manager, because you’ll need it when connecting directly to the database, and choose the region closest to your users - for Europe, the nearest European one.

After a few minutes the project is ready, and underneath runs standard PostgreSQL, which you can take anywhere if you migrate.

Step 2. First Table

You can create a table in the table editor, clicking like in a spreadsheet, or in the SQL editor. The official guide shows the SQL Editor version: you create a simple table, for example a list of instruments with an ID and name, and add a few sample rows. Even if you don’t know SQL, the commands from the guide are enough to copy and run.

Step 3. Securing the Table with Row Level Security

This is the step your data security depends on. Row Level Security is rules that define who can read and modify which rows. The official guide enables it for the table and adds a rule that allows everyone to only read the list of instruments. For a public list, that’s fine. For customer data, the rule must allow each person to see only their own rows.

A table without these rules, exposed through the API, is the most common cause of leaks in quickly-built applications. We wrote about this in more detail in the guide. The rule is simple: no table with user data goes into the app without access rules enabled.

Step 4. Project URL and Public Key

Your app needs two things you’ll find in the Connect panel in your project: the project URL and the public key. You paste them into your app’s settings file. The public key can go to the browser, because access to data is controlled by the rules from the previous step.

If your app doesn’t see the data, check whether the Data API is enabled in the integration settings.

Step 5. Connecting to Your App

Supabase has ready-made guides for over a dozen technologies, from Next.js, React and Vue to Flutter, Python and Laravel. For Next.js, the entire start comes down to one command creating an app with a ready connection, pasting the URL and key, then writing a page that fetches data from the table. After launching the app, you see on the page the rows you added in step two.

If you’re building in Lovable or a similar tool, it performs most of these steps for you, but checking the access rules is still your responsibility.

Step 6. Authentication and Files

Once the table works, you add other elements the same way. User authentication you enable in the authentication section, choosing methods like email or Google account. Files, like profile photos or attachments, you keep in file storage, which also has its own access rules. For more complex logic there are functions that run server-side.

Most Common Mistakes at the Start

• Table without access rules exposed in the app.
• Service key in browser code instead of the public key.
• Region on the other side of the world, making every query take longer.
• No backup before major changes to the database structure.

When to Move to the Pro Plan

The free plan is enough for learning and prototypes, but unused projects are paused on it. When your app has real users, the project can’t go to sleep, and that’s when the Pro plan stops being optional.

How to Check if Your Data Is Secure

After connecting your app, log in as two different people and check whether each sees only their own data. This is the simplest test that catches the most dangerous errors. Also review the list of tables in the panel and make sure each one exposed in the API has access rules enabled. Supabase warns in the panel about tables without these rules, so it’s worth not ignoring those warnings.

// read moreSupabase: Ready-Made App Backend and One Security MistakeAI ToolsSupabase Use Cases: Backend for Apps, Forms, and User AccountsGuides110 Searches Worth More Than 3,600: CPC vs Volume AnalysisGuides

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