Supabase

# Supabase Core Skill


Core concepts, CLI workflow, and patterns common to all Supabase projects.

**Sources:** [Supabase Docs](https://supabase.com/docs) | [Supabase CLI](https://supabase.com/docs/guides/local-development/cli/getting-started)

---

## Core Principle

**Local-first, migrations in version control, never touch production directly.**

Develop locally with the Supabase CLI, capture all changes as migrations, and deploy through CI/CD.

---

## Supabase Stack

| Service | Purpose |
|---------|---------|
| **Database** | PostgreSQL with extensions |
| **Auth** | User authentication, OAuth providers |
| **Storage** | File storage with RLS |
| **Edge Functions** | Serverless Deno functions |
| **Realtime** | WebSocket subscriptions |
| **Vector** | AI embeddings (pgvector) |

---

## CLI Setup

### Install & Login
```bash
# macOS
brew install supabase/tap/supabase

# npm (alternative)
npm install -g supabase

# Login
supabase login
```

### Initialize Project
```bash
# In your project directory
supabase init

# Creates:
# supabase/
# ├── config.toml      # Local config
# ├── seed.sql         # Seed data
# └── migrations/      # SQL migrations
```

### Link to Remote
```bash
# Get project ref from dashboard URL: https://supabase.com/dashboard/project/<ref>
supabase link --project-ref <project-id>

# Pull existing schema
supabase db pull
```

### Start Local Stack
```bash
supabase start

# Output:
# API URL: http://localhost:54321
# GraphQL URL: http://localhost:54321/graphql/v1
# DB URL: postgresql://postgres:postgres@localhost:54322/postgres
# Studio URL: http://localhost:54323
# Anon key: eyJ...
# Service role key: eyJ...
```

---

## Migration Workflow

### Option 1: Dashboard + Diff (Quick Prototyping)
```bash
# 1. Make changes in local Studio (localhost:54323)
# 2. Generate migration from diff
supabase db diff -f <migration_name>

# 3. Review generated SQL
cat supabase/migrations/*_<migration_name>.sql

# 4. Reset to test
supabase db reset
```

### Option 2: Write Migrations Directly (Recommended)
```bash
# 1. Create empty migration
supabase migration new create_users_table

# 2. Edit the migration file
# supabase/migrations/<timestamp>_create_users_table.sql

# 3. Apply locally
supabase db reset
```

### Option 3: ORM Migrations (Best DX)
Use Drizzle (TypeScript) or SQLAlchemy (Python) - see framework-specific skills.

### Deploy Migrations
```bash
# Push to remote (staging/production)
supabase db push

# Check migration status
supabase migration list
```

---

## Database Patterns

### Enable RLS on All Tables
```sql
-- Always enable RLS
ALTER TABLE public.profiles ENABLE ROW LEVEL SECURITY;

-- Default deny - must create policies
CREATE POLICY "Users can view own profile"
  ON public.profiles
  FOR SELECT
  USING (auth.uid() = id);
```

### Common RLS Policies
```sql
-- Public read
CREATE POLICY "Public read access"
  ON public.posts FOR SELECT
  USING (true);

-- Authenticated users only
CREATE POLICY "Authenticated users can insert"
  ON public.posts FOR INSERT
  WITH CHECK (auth.role() = 'authenticated');

-- Owner access
CREATE POLICY "Users can update own records"
  ON public.posts FOR UPDATE
  USING (auth.uid() = user_id);

-- Admin access (using custom claim)
CREATE POLICY "Admins have full access"
  ON public.posts FOR ALL
  USING (auth.jwt() ->> 'role' = 'admin');
```

### Link to auth.users
```sql
-- Profile table linked to auth
CREATE TABLE public.profiles (
  id UUID PRIMARY KEY REFERENCES auth.users(id) ON DELETE CASCADE,
  username TEXT UNIQUE NOT NULL,
  avatar_url TEXT,
  created_at TIMESTAMPTZ DEFAULT NOW()
);

-- Auto-create profile on signup
CREATE OR REPLACE FUNCTION public.handle_new_user()
RETURNS TRIGGER AS $$
BEGIN
  INSERT INTO p