Supabase Developer

Supabase Developer Skill

Overview

This skill provides comprehensive expertise in building production-ready applications with Supabase, the open-source Firebase alternative. It covers database design, authentication, Row Level Security (RLS), file storage, Edge Functions, and real-time subscriptions. Edge Functions now run on Deno 2.1 by default (full rollout August 2025), with local preview available since March 2025.

Core Capabilities

Database & PostgreSQL

• Schema Design: Normalized tables with proper relationships and indexes
• Migrations: Version-controlled database changes
• Queries: Complex queries with joins, CTEs, and aggregations
• Functions: PostgreSQL stored procedures and triggers
• Extensions: PostGIS, pg_vector, pgcrypto, and more

Authentication

• Email/Password: Traditional authentication flow
• Magic Links: Passwordless email authentication
• OAuth Providers: Google, GitHub, Discord, Twitter, and more
• Phone Auth: SMS-based authentication
• Multi-Factor Authentication: TOTP and SMS verification
• Session Management: JWT tokens and refresh handling

Row Level Security (RLS)

• Policy Design: Secure data access patterns
• User-based Access: Policies tied to authenticated users
• Role-based Access: Custom roles and permissions
• Organization-based: Multi-tenant security patterns
• Performance: Optimized RLS with proper indexing

Storage

• File Uploads: Direct and resumable uploads
• Access Control: Bucket policies and RLS integration
• Transformations: Image resizing and optimization
• CDN: Global content delivery
• Signed URLs: Temporary access tokens

Edge Functions

• Deno 2.1 Runtime: TypeScript/JavaScript edge computing with seamless npm imports, native TypeScript support, Web API compatibility, and better performance
• Dashboard Editor: In-dashboard Edge Functions editor for quick updates and prototyping
• AI Assistant: Built-in AI assistant for generating function code
• API Routes: Custom backend logic
• Webhooks: Event-driven integrations
• Scheduled Tasks: Cron-based functions (pg_cron)
• Third-party APIs: External service integrations
• No-Docker Deploy: Deploy with supabase functions deploy --no-docker when Docker isn't available

Realtime

• Database Changes: Listen to INSERT, UPDATE, DELETE
• Broadcast: Publish messages to channels
• Presence: Track online users and state
• Postgres Changes: Row-level change subscriptions

Implementation Patterns

Project Structure

├── supabase/
│   ├── config.toml           # Project configuration
│   ├── migrations/           # Database migrations
│   │   ├── 20240101000000_initial_schema.sql
│   │   └── 20240102000000_add_profiles.sql
│   ├── functions/            # Edge Functions
│   │   ├── hello-world/
│   │   │   └── index.ts
│   │   └── _shared/          # Shared utilities
│   │       └── cors.ts
│   └── seed.sql              # Development seed data
├── src/
│   ├── lib/
│   │   └── supabase.ts       # Client initialization
│   ├── types/
│   │   └── database.types.ts # Generated types
│   └── ...
└── package.json

Database Schema Example

-- Users profile extension
create table public.profiles (
  id uuid references auth.users on delete cascade primary key,
  username text unique not null,
  full_name text,
  avatar_url text,
  created_at timestamptz default now() not null,
  updated_at timestamptz default now() not null
);

-- Enable RLS
alter table public.profiles enable row level security;

-- RLS Policies
create policy "Public profiles are viewable by everyone"
  on public.profiles for select
  using (true);

create policy "Users can update their own profile"
  on public.profiles for update
  using (auth.uid() = id);

-- Trigger for updated_at
create trigger handle_updated_at
  before update on public.profiles
  for each row execute function moddatetime(updated_at);

Client Initialization

// src/lib/supabase.ts
import { createClient } from '@supabase/supabase-js'
import type { Database } from '@/types/database.types'

const supabaseUrl = process.env.NEXT_PUBLIC_SUPABASE_URL!
const supabaseAnonKey = process.env.NEXT_PUBLIC_SUPABASE_ANON_KEY!

export const supabase = createClient<Database>(
  supabaseUrl,
  supabaseAnonKey
)

Authentication Patterns

// Sign up with email
const { data, error } = await supabase.auth.signUp({
  email: 'user@example.com',
  password: 'secure-password',
  options: {
    data: {
      full_name: 'John Doe'
    }
  }
})

// Sign in with OAuth
const { data, error } = await supabase.auth.signInWithOAuth({
  provider: 'google',
  options: {
    redirectTo: `${window.location.origin}/auth/callback`
  }
})

// Get current user
const { data: { user } } = await supabase.auth.getUser()

// Listen to auth changes
supabase.auth.onAuthStateChange((event, session) => {
  if (event === 'SIGNED_IN') {
    // Handle sign in
  }
})

Database Queries

// Select with relations
const { data: posts, error } = await supabase
  .from('posts')
  .select(`
    id,
    title,
    content,
    author:profiles(username, avatar_url),
    comments(id, content, created_at)
  `)
  .eq('published', true)
  .order('created_at', { ascending: false })
  .range(0, 9)

// Insert with returning
const { data: post, error } = await supabase
  .from('posts')
  .insert({
    title: 'New Post',
    content: 'Content here',
    author_id: user.id
  })
  .select()
  .single()

// Update with filters
const { error } = await supabase
  .from('posts')
  .update({ published: true })
  .eq('id', postId)
  .eq('author_id', user.id)

// Delete with cascade
const { error } = await supabase
  .from('posts')
  .delete()
  .eq('id', postId)

Storage Operations

// Upload file
const { data, error } = await supabase.storage
  .from('avatars')
  .upload(`${userId}/avatar.png`, file, {
    cacheControl: '3600',
    upsert: true
  })

// Get public URL
const { data: { publicUrl } } = supabase.storage
  .from('avatars')
  .getPublicUrl(`${userId}/avatar.png`)

// Download file
const { data, error } = await supabase.storage
  .from('documents')
  .download('report.pdf')

// Create signed URL
const { data, error } = await supabase.storage
  .from('private')
  .createSignedUrl('file.pdf', 3600)

Realtime Subscriptions

// Subscribe to database changes
const channel = supabase
  .channel('posts-changes')
  .on(
    'postgres_changes',
    {
      event: '*',
      schema: 'public',
      table: 'posts',
      filter: 'published=eq.true'
    },
    (payload) => {
      console.log('Change:', payload)
    }
  )
  .subscribe()

// Broadcast messages
const channel = supabase.channel('room-1')
channel.subscribe((status) => {
  if (status === 'SUBSCRIBED') {
    channel.send({
      type: 'broadcast',
      event: 'cursor',
      payload: { x: 100, y: 200 }
    })
  }
})

// Presence tracking
const channel = supabase.channel('online-users')
channel.on('presence', { event: 'sync' }, () => {
  const state = channel.presenceState()
  console.log('Online users:', state)
})
channel.subscribe(async (status) => {
  if (status === 'SUBSCRIBED') {
    await channel.track({ user_id: user.id, online_at: new Date() })
  }
})

// Cleanup
supabase.removeChannel(channel)

Edge Function Example

// supabase/functions/send-email/index.ts (Deno 2.1)
import "jsr:@supabase/functions-js/edge-runtime.d.ts"
import { createClient } from 'npm:@supabase/supabase-js@2'

const corsHeaders = {
  'Access-Control-Allow-Origin': '*',
  'Access-Control-Allow-Headers': 'authorization, x-client-info, apikey, content-type',
}

Deno.serve(async (req) => {
  if (req.method === 'OPTIONS') {
    return new Response('ok', { headers: corsHeaders })
  }

  try {
    const supabase = createClient(
      Deno.env.get('SUPABASE_URL')!,
      Deno.env.get('SUPABASE_SERVICE_ROLE_KEY')!
    )

    const { email, subject, body } = await req.json()

    // Your email sending logic here

    return new Response(
      JSON.stringify({ success: true }),
      { headers: { ...corsHeaders, 'Content-Type': 'application/json' } }
    )
  } catch (error) {
    return new Response(
      JSON.stringify({ error: error.message }),
      { status: 400, headers: { ...corsHeaders, 'Content-Type': 'application/json' } }
    )
  }
})

Edge Function Management API

Use the Management API for programmatic deploys and updates in CI/CD pipelines or automated workflows.

curl -X POST "https://api.supabase.com/v1/projects/{ref}/functions" \
  -H "Authorization: Bearer $SUPABASE_ACCESS_TOKEN" \
  -H "Content-Type: application/json" \
  -d '{"name": "hello-world", "slug": "hello-world", "verify_jwt": true}'

Best Practices

Security

• Always enable RLS on public tables
• Use service role key only server-side
• Validate inputs in Edge Functions
• Implement proper auth checks
• Use parameterized queries
• Review RLS policies regularly

Performance

• Add indexes for frequently queried columns
• Use select() to limit returned columns
• Implement pagination with range()
• Use database functions for complex operations
• Enable connection pooling in production
• Use head: true for count-only queries

Architecture

• Keep migrations small and focused
• Use database triggers for side effects
• Implement proper error handling
• Generate and use TypeScript types
• Organize Edge Functions by domain
• Use shared utilities in _shared/

Development Workflow

• Use Supabase CLI for local development; use the dashboard editor and AI assistant for quick prototypes, and rely on the CLI or Management API for production workflows
• Test RLS policies before deployment
• Seed database for consistent testing
• Use branching for schema changes
• Document all RLS policies

Scripts

This skill includes executable scripts in the scripts/ folder:

Project Setup

• setup-project.sh: Initialize new Supabase project with configuration

  ./scripts/setup-project.sh <project-name>
  

• local-dev.sh: Start local Supabase development environment

  ./scripts/local-dev.sh [--reset]
  

Database

• create-migration.sh: Create a new timestamped migration file

  ./scripts/create-migration.sh <migration-name>
  

• run-migrations.sh: Apply pending migrations

  ./scripts/run-migrations.sh [--local|--remote]
  

• seed-database.sh: Seed database with test data

  ./scripts/seed-database.sh
  

• generate-types.sh: Generate TypeScript types from database schema

  ./scripts/generate-types.sh [--output PATH]
  

• link-project.sh: Link local project to remote Supabase project

  ./scripts/link-project.sh <project-ref>
  

Edge Functions

• create-function.sh: Create a new Edge Function with boilerplate

  ./scripts/create-function.sh <function-name>
  

• deploy-function.sh: Deploy Edge Function to production (supports --no-docker when Docker isn't available)

  ./scripts/deploy-function.sh <function-name> [--all]
  

• serve-functions.sh: Run Edge Functions locally for testing

  ./scripts/serve-functions.sh
  

Testing & Security

• setup-testing.sh: Set up testing environment with Vitest

  ./scripts/setup-testing.sh
  

• run-tests.sh: Run tests with various options

  ./scripts/run-tests.sh [--watch] [--ui] [--coverage]
  

• test-rls.sh: Test RLS policies with different user contexts

  ./scripts/test-rls.sh <table-name>
  

• backup-database.sh: Create database backup

  ./scripts/backup-database.sh [--output PATH]
  

Templates

This skill includes production-ready templates in the templates/ folder:

Database

• schema-base.sql: Complete base schema with profiles, posts, comments, RLS policies, triggers, and indexes
• rls-policies.sql: Comprehensive RLS policy patterns library (10+ patterns including user-owned, org-based, role-based, time-based, and more)

Client Code

• supabase-client.ts: Type-safe client initialization with browser, server, and admin clients plus utility functions
• auth-helpers.ts: Complete authentication utilities including email/password, OAuth, magic links, phone auth, MFA, and React hooks
• storage-helpers.ts: File upload/download utilities with progress tracking, image compression, bucket management, and React hooks

Edge Functions

• edge-function-complete.ts: Complete Edge Function template with CORS, authentication, validation, error handling, and common patterns (webhooks, scheduled tasks, email, external APIs, rate limiting)

Resources

This skill includes detailed reference guides in the resources/ folder:

• database-patterns.md: Schema design, queries, migrations, and PostgreSQL features
• authentication.md: Auth flows, providers, sessions, and MFA
• row-level-security.md: RLS policy patterns and multi-tenant security
• storage.md: File storage, access control, and transformations
• edge-functions.md: Deno 2.1 runtime, dashboard editor, AI assistant, Management API, deployment, and best practices
• realtime.md: Subscriptions, broadcast, and presence
• client-libraries.md: JavaScript, Python, and other client usage

Specialization: Supabase Full-Stack Development Version: 2.0 Last Updated: May 2026