Use Supabase with Android Kotlin

Help me add Supabase to my Android Kotlin project. Create a Supabase project at
database.new and run the instruments table SQL. Then:
1. Create a new Android project in Android Studio.
2. Add the Kotlin serialization plugin, Ktor client, and Supabase BOM to
   `build.gradle.kts`.
3. Add `<uses-permission android:name="android.permission.INTERNET" />` to
   `AndroidManifest.xml`.
4. Initialize the Supabase client in `MainActivity.kt` with your project URL
   and publishable key.
5. Add a serializable `Instrument` data class.
6. Use `LaunchedEffect` and `LazyColumn` to fetch and display the instruments
   table.
7. Click Run in Android Studio to start the app.

REFERENCE
https://supabase.com/docs/guides/getting-started/quickstarts/kotlin.md

1. Create a Supabase project

To start, you need a Supabase project.

Create a new Supabase project from the Dashboard of any organization you belong to.

2. Set up your database

When your Supabase project is up and running, create an instruments table with some sample data. Then set only the privileges each Postgres role needs, add Row Level Security (RLS) for enhanced security for database data by default, and create an RLS policy to make the data in the table publicly readable.

Do these steps within your project's dashboard by copying and running the snippet in your project's SQL Editor.

-- Create the table
create table instruments (
  id bigint primary key generated always as identity,
  name text not null
);

-- Insert sample data into the table
insert into instruments (name)
values
  ('violin'),
  ('viola'),
  ('cello');

-- Grant the privileges the role needs, which is read access
grant select on public.instruments to anon;

-- Enable row level security for the table
alter table instruments enable row level security;

-- Create a policy to allow the anon role to read from the instruments table
create policy "public can read instruments"
on public.instruments
for select to anon
using (true);

3. Create an Android app with Android Studio

Select the Android Studio > New > New Android Project menu item.

4. Set up AI tooling (optional)

Supabase provides two ways to give AI tools context about your project: Agent Skills, which give your AI coding agent procedural knowledge, and the MCP server, which connects AI assistants to your Supabase project directly.

Agent Skills

Agent Skills is a curated set of instructions that give your AI agent procedural knowledge about working with Supabase.

Install them so your AI coding agent can produce more accurate, reliable code using current Supabase patterns, such as authentication, server-side rendering, and database migrations, rather than relying solely on training data.

Installing Agent Skills

To install, run the following command in the root of your project:

npx skills add supabase/agent-skills

Supabase MCP server

The Supabase MCP server connects AI assistants to Supabase, so they can inspect your schema and act on your projects on your behalf. Find out how to add it to your client in the MCP docs.

5. Install dependencies

Open build.gradle.kts (app) file and add the serialization plugin, Ktor client, and Supabase client.

Replace the version placeholders $kotlin_version with the Kotlin version of the project, and $supabase_version and $ktor_version with the respective latest versions. For example, Kotlin 2.2.21, supabase-kt BOM 3.5.0, and Ktor 3.0.3.

id("org.jetbrains.kotlin.plugin.compose") version "$kotlin_version" apply false

id("org.jetbrains.kotlin.plugin.compose")

plugins {
  ...
  kotlin("plugin.serialization") version "$kotlin_version"
}
...
dependencies {
  ...
  implementation(platform("io.github.jan-tennert.supabase:bom:$supabase_version"))
  implementation("io.github.jan-tennert.supabase:postgrest-kt")
  implementation("io.ktor:ktor-client-android:$ktor_version")
}

6. Add internet access permission

Add the following line to the AndroidManifest.xml file under the manifest tag and outside the application tag.

...
<uses-permission android:name="android.permission.INTERNET" />
...

7. Initialize the Supabase client

You can create a Supabase client whenever you need to perform an API call.

For a quick example, create a client at the top of the MainActivity.kt file below the imports.

Replace the supabaseUrl and supabaseKey with your own, which you can get from the helper below, or from the project Connect panel:

import io.github.jan.supabase.postgrest.from
import ...

val supabase = createSupabaseClient(
    supabaseUrl = "YOUR_SUPABASE_URL",
    supabaseKey = "YOUR_SUPABASE_PUBLISHABLE_KEY"
  ) {
    install(Postgrest)
}
...

Get API details

To interact with data in database tables, you use the client libraries that wrap the auto-generated Data API endpoints, authenticating using the Project URL and key from the project Connect dialog.

Project URL: https://<project-ref>.supabase.co (find yours in the dashboard)

Publishable key: sb_publishable_... (find yours in the dashboard)

8. Create a data model for instruments

Create a serializable data class to represent the data from the database.

Add the following below the createSupabaseClient function in the MainActivity.kt file.

import kotlinx.serialization.Serializable

@Serializable
data class Instrument(
    val id: Int,
    val name: String,
)

9. Query data from the app

Use LaunchedEffect to fetch data from the database and display it in a LazyColumn.

Replace the default MainActivity class with the following code.

class MainActivity : ComponentActivity() {
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContent {
            // A surface container using the 'background' color from the theme
            Surface(
                modifier = Modifier.fillMaxSize(),
                color = MaterialTheme.colorScheme.background
            ) {
                InstrumentsList()
            }
        }
    }
}

@Composable
fun InstrumentsList() {
    var instruments by remember { mutableStateOf<List<Instrument>>(listOf()) }
    var error by remember { mutableStateOf<String?>(null) }
    LaunchedEffect(Unit) {
        withContext(Dispatchers.IO) {
            try {
                instruments = supabase.from("instruments")
                                  .select().decodeList<Instrument>()
            } catch (e: Exception) {
                error = e.message
            }
        }
    }
    if (error != null) {
        Text(
            "Error loading instruments: $error",
            modifier = Modifier.padding(8.dp),
        )
        return
    }
    LazyColumn {
        items(
            instruments,
            key = { instrument -> instrument.id },
        ) { instrument ->
            Text(
                instrument.name,
                modifier = Modifier.padding(8.dp),
            )
        }
    }
}

10. Start the app

Run the app on an emulator or a physical device by clicking the Run app button in Android Studio.

Production requirements

The quickstart procedure in this guide optimizes for getting you to a working app, not for production.

Before you deploy:

• If your app reads or writes through the Data API, review your Row Level Security policies. Any policy you added here is scoped to this quickstart's sample data, not to real user data.
• Set your Supabase credentials as environment variables on whatever platform you deploy to, rather than committing them to source control.
• Configure a custom domain for your Supabase project once you're ready to go live.

Next steps

• Learn how to build a complete user management app with authentication in the Kotlin tutorial
• Explore the supabase-kt library on GitHub
• Insert more data into your database
• Upload and serve static files using Storage