Supabase Self-Hosted API Gateway: From Domain Setup to Security Nirvana!

G: So, you’ve decided to take the reins and self-host your Supabase instance. That’s a fantastic move for ultimate control, cost efficiency, and compliance! But as you delve deeper, you’ll quickly realize that simply running the Docker containers isn’t enough for a production-ready setup. This is where an API Gateway steps in – a crucial component that acts as the single entry point for all your Supabase services, handling everything from domain routing to robust security.

This guide will walk you through the essential steps to set up a powerful API Gateway for your self-hosted Supabase, covering domain configuration, certificate management, and a deep dive into security optimization. Let’s get started! 🚀

1. Why an API Gateway for Self-Hosted Supabase? 🤔

Before we get our hands dirty, let’s understand why an API Gateway is indispensable for your self-hosted Supabase setup.

Supabase, at its core, is a collection of open-source tools:

• PostgREST: Exposes your PostgreSQL database as a REST API.
• GoTrue: Handles authentication (users, JWTs).
• Storage: Manages file storage.
• Realtime: Provides WebSocket subscriptions.
• Edge Functions: Serverless functions.

Each of these components typically runs on a different port within your server or Docker network. Without an API Gateway, you’d have to expose multiple ports to the internet and tell your clients to connect to your-ip:8000 for PostgREST, your-ip:9999 for Auth, and so on. This is:

• Insecure: Exposing raw ports increases attack surface.
• Complicated: Clients need to know multiple endpoints.
• Inefficient: No centralized control over traffic.
• Lacking Features: No easy way to implement rate limiting, WAF, unified logging, or custom domains.

An API Gateway solves all these problems by:

• Unified Access: Providing a single, clean domain (e.g., api.yourdomain.com) for all services.
• Domain Mapping: Routing requests based on subdomains or paths to the correct internal service.
• SSL/TLS Termination: Encrypting all traffic from clients to your gateway.
• Security Layer: Implementing features like rate limiting, Web Application Firewall (WAF), and authentication pre-checks.
• Load Balancing: Distributing traffic if you scale to multiple instances.
• Observability: Centralized logging and monitoring.

Think of it as the friendly front desk for your entire Supabase backend, directing traffic and ensuring security. 🛡️

2. Choosing Your API Gateway: Nginx, Caddy, or Traefik? 🛠️

Several excellent API Gateway options exist, each with its strengths. For self-hosted scenarios, the most popular choices are:

• Nginx: The classic “Swiss Army Knife” of web servers and reverse proxies. Highly performant, incredibly flexible, and well-documented. However, manual SSL certificate management (unless using certbot) can be a bit tedious.

  • Pros: Battle-tested, high performance, immense flexibility.
  • Cons: Configuration can be complex, SSL setup requires extra steps.

• Caddy: A modern, open-source web server that emphasizes simplicity and automatic HTTPS. It automatically obtains and renews SSL certificates from Let’s Encrypt, making setup a breeze.

  • Pros: Automatic HTTPS (game-changer!), simple Caddyfile configuration, great for Docker.
  • Cons: Less feature-rich than Nginx for very advanced use cases, newer kid on the block (though very stable).

• Traefik: Built for the cloud-native era, Traefik integrates seamlessly with Docker, Kubernetes, and other orchestrators. It automatically discovers services and configures routing.

  • Pros: Dynamic configuration, service discovery, great for highly dynamic environments.
  • Cons: Can be overkill for a single-server self-hosted setup, configuration can be more abstract.

Our Recommendation for Self-Hosted Supabase: For most users, Caddy strikes the perfect balance between ease of use and powerful features, especially with its automatic HTTPS. We’ll primarily use Caddy for our examples, but the principles apply to Nginx too.

3. Domain Setup: The Foundation 🗺️

Before your API Gateway can do its magic, you need to own a domain and configure its DNS records.

3.1 Registering Your Domain

First, purchase a domain (e.g., yourdomain.com) from a reputable registrar like Namecheap, Cloudflare, GoDaddy, etc.

3.2 DNS Configuration

This is where you tell the internet that your chosen subdomains point to your server’s IP address.

Let’s assume your server’s public IP address is 192.0.2.1. You’ll want to create A records (or CNAME if pointing to another domain) for each Supabase component you want to expose. A common strategy is to use subdomains:

• api.yourdomain.com (for PostgREST)
• auth.yourdomain.com (for GoTrue)
• storage.yourdomain.com (for Storage)
• realtime.yourdomain.com (for Realtime)
• functions.yourdomain.com (for Edge Functions)
• studio.yourdomain.com (optional, for the Supabase Studio dashboard)

Example DNS Records (in your domain registrar’s DNS settings):

Important: DNS changes can take a few minutes to several hours to propagate globally. You can use tools like dig or online DNS checkers (e.g., dnschecker.org) to verify propagation.

4. Implementing the API Gateway (with Caddy and Docker) 🐳

For this section, we’ll assume you have Docker and Docker Compose installed on your server. We’ll integrate Caddy with a basic Supabase self-hosted setup.

4.1 Prerequisites

• A Linux server (VPS, cloud instance) with Docker and Docker Compose installed.
• Your configured domains pointing to your server’s public IP.
• Basic understanding of docker-compose.yml.

4.2 Supabase Self-Hosted Setup (Brief Overview)

Refer to the official Supabase self-hosting guide on GitHub for the complete setup. Essentially, you’ll clone their supabase/supabase repository and set up your .env file.

Make sure your Supabase services are not directly exposed to the internet. They should run on your Docker internal network. For example, PostgREST might be on port 8000, GoTrue on 9999, etc., within the Docker network.

4.3 Caddy Configuration (Caddyfile)

Create a file named Caddyfile in the same directory where your docker-compose.yml (for Supabase services) will reside, or in a dedicated caddy subdirectory.

# Global options for Caddy
{
    email your@email.com # Used by Let's Encrypt for certificate notifications
    log {
        output stdout
        format json
    }
}

# PostgREST API Gateway
api.yourdomain.com {
    reverse_proxy supabase-rest-api:8000 {
        # Important: Pass the original Host header to the backend
        header_up Host {http.request.host}
    }
    # Optional: Basic rate limiting to prevent abuse
    # rate_limit {
    #     requests 100
    #     interval 1s
    #     burst 200
    #     variable client.ip
    #     zone api_ratelimit
    #     response "Too many requests. Please try again later."
    #     status 429
    # }
}

# GoTrue (Authentication) API Gateway
auth.yourdomain.com {
    reverse_proxy supabase-auth:9999 {
        header_up Host {http.request.host}
    }
}

# Storage API Gateway
storage.yourdomain.com {
    reverse_proxy supabase-storage:5000 {
        header_up Host {http.request.host}
    }
}

# Realtime API Gateway (WebSockets)
realtime.yourdomain.com {
    reverse_proxy supabase-realtime:4000 {
        header_up Host {http.request.host}
    }
    # For WebSockets, Caddy automatically handles upgrade headers, but it's good to be explicit
    header_up Connection {http.request.header.Connection}
    header_up Upgrade {http.request.header.Upgrade}
}

# Edge Functions API Gateway
functions.yourdomain.com {
    reverse_proxy supabase-functions:8000 { # Assuming functions is on 8000 by default, adjust if different
        header_up Host {http.request.host}
    }
}

# Optional: Supabase Studio Dashboard
studio.yourdomain.com {
    reverse_proxy supabase-studio:3000 { # Or whatever port Studio runs on
        header_up Host {http.request.host}
    }
}

Explanation of the Caddyfile:

• email your@email.com: Essential for Let’s Encrypt to issue and renew certificates.
• log: Configures logging output.
• api.yourdomain.com: This block defines the configuration for requests coming to api.yourdomain.com.
• reverse_proxy supabase-rest-api:8000: This is the core. It tells Caddy to forward all requests for api.yourdomain.com to the Docker service named supabase-rest-api on port 8000. Replace supabase-rest-api with the actual service name from your Supabase docker-compose.yml.
• header_up Host {http.request.host}: This is crucial! Supabase services (especially GoTrue and PostgREST) rely on the Host header to generate correct URLs (e.g., for email verification links or API documentation). This directive ensures the original domain name is passed to the backend.
• rate_limit: An example of how to implement a basic rate limit. Uncomment and adjust as needed.

4.4 Docker Compose Integration

Now, let’s add Caddy to your docker-compose.yml. You’ll need to ensure Caddy and your Supabase services are on the same Docker network so they can communicate.

Here’s a simplified docker-compose.yml snippet, showing how Caddy integrates. You’ll merge this with your existing Supabase services definition.

version: '3.8'

services:
  # Caddy API Gateway
  caddy:
    image: caddy/caddy:latest
    container_name: caddy
    restart: unless-stopped
    ports:
      - "80:80"   # HTTP for ACME challenges and redirection to HTTPS
      - "443:443" # HTTPS for all encrypted traffic
    volumes:
      - ./Caddyfile:/etc/caddy/Caddyfile # Your Caddy configuration
      - caddy_data:/data                 # Persistent storage for SSL certs and data
      - caddy_config:/config             # Persistent storage for Caddy config
    networks:
      - supabase_network # Ensure Caddy is on the same network as Supabase services

  # Example Supabase services (replace with your actual service names and configurations)
  supabase-rest-api:
    image: postgrest/postgrest:latest # Example image
    container_name: supabase-rest-api
    restart: unless-stopped
    # ... other configurations (environment variables, depends_on, etc.)
    networks:
      - supabase_network
    # IMPORTANT: Do NOT expose ports to the host like '8000:8000' if Caddy is handling it.
    # The service just needs to be reachable internally on the network.

  supabase-auth:
    image: supabase/gotrue:latest # Example image
    container_name: supabase-auth
    restart: unless-stopped
    # ... other configurations
    networks:
      - supabase_network
    environment:
      # Crucial for GoTrue to know its external URL for redirects/emails
      GOTRUE_URL: "https://auth.yourdomain.com" 
      SITE_URL: "https://auth.yourdomain.com"
      # Other Supabase specific env vars (JWT_SECRET, DB_URL, etc.)

  # Add other Supabase services (storage, realtime, functions, studio) similarly...

networks:
  supabase_network:
    # Ensure this network is defined, or use an existing one
    # For a simple setup, a default bridge network might suffice,
    # but a custom bridge network is better practice.

volumes:
  caddy_data:
  caddy_config:
  # Define other volumes for Supabase services (db, storage, etc.)

Key Points for Docker Compose:

• ports for Caddy: Only Caddy exposes ports 80 and 443 to the host. All other Supabase services should not expose their ports directly.
• volumes for Caddy: caddy_data is crucial for Caddy to store its Let’s Encrypt certificates persistently. caddy_config for internal config.
• networks: Ensure Caddy and all Supabase services are on the same Docker network (supabase_network in this example). This allows them to communicate using their service names (e.g., supabase-rest-api).
• Environment Variables: For Supabase services like GoTrue, make sure to set GOTRUE_URL, SITE_URL, PUBLIC_SUPABASE_URL, SUPABASE_URL, PUBLIC_SUPABASE_ANON_KEY etc., to their external, public URLs (e.g., https://auth.yourdomain.com, https://api.yourdomain.com). This is vital for Supabase to generate correct links in emails, JWTs, and client SDKs.

4.5 Deploying

Once your Caddyfile and docker-compose.yml are set up, navigate to the directory containing them in your server’s terminal and run:

docker compose up -d

Caddy will start, automatically attempt to obtain SSL certificates for your specified domains from Let’s Encrypt, and then proxy requests. If there are any DNS propagation issues or firewall blocks (ensure ports 80 and 443 are open!), Caddy will report errors in its logs (docker compose logs caddy).

5. Security Optimization: Beyond the Basics 🔒✨

Setting up your API Gateway is a big step, but security is an ongoing process. Here’s how to optimize your setup for maximum protection:

5.1 TLS/SSL Encryption (Automatic with Caddy)

• Importance: All communication between your clients and your API Gateway must be encrypted using HTTPS. Caddy handles this automatically with Let’s Encrypt, ensuring a padlock icon in your users’ browsers.
• Best Practices:
  • Ensure all http:// requests are automatically redirected to https://. (Caddy does this by default if you listen on port 80).
  • Use strong cipher suites. (Caddy uses modern, secure defaults).
  • Regularly check certificate expiry. (Caddy handles auto-renewal).

5.2 Rate Limiting ⏱️

• Purpose: Prevents abuse, brute-force attacks, and denial-of-service (DoS) attempts by limiting the number of requests a single client (e.g., by IP address) can make within a certain timeframe.
• Implementation (Caddy Example – as seen in Caddyfile snippet):

  api.yourdomain.com {
      # ... other configurations ...
      rate_limit {
          requests 100        # Max 100 requests
          interval 1s         # Per 1 second
          burst 200           # Allow temporary burst up to 200 requests
          variable client.ip  # Rate limit based on client IP
          response "Too many requests. Please try again later."
          status 429
      }
  }

• Strategy: Apply stricter rate limits to sensitive endpoints (e.g., login, password reset) and more lenient ones to general read operations.

5.3 Web Application Firewall (WAF) 🛡️

• Purpose: Provides an additional layer of security by filtering and monitoring HTTP traffic between a web application and the internet. It protects against common web vulnerabilities like SQL injection, cross-site scripting (XSS), and more, by inspecting payloads.
• Implementation:
  • Nginx: You can integrate Nginx with ModSecurity (an open-source WAF engine). This requires recompiling Nginx with ModSecurity or using a pre-built image.
  • Cloudflare/AWS WAF: For public-facing applications, using a cloud-based WAF service like Cloudflare (which also provides DDoS protection and caching) or AWS WAF is highly recommended. You’d point your domain’s DNS to their services, and they would proxy traffic to your API Gateway.

5.4 Authentication & Authorization 🔑

• Supabase’s Role: Supabase’s GoTrue service handles user authentication (signup, login, password reset) and issues JSON Web Tokens (JWTs). PostgREST and Storage use these JWTs for row-level security and access control.
• API Gateway’s Role: The API Gateway ensures that clients can reach GoTrue and then correctly forwards the JWTs provided by clients to the downstream Supabase services. It can also perform basic JWT validation (e.g., check for malformed tokens) before forwarding, offloading some work from the backend.
• Best Practices:
  • Always enforce HTTPS for all authentication-related endpoints.
  • Ensure your GOTRUE_JWT_SECRET (and other secrets) are strong and kept secure.

5.5 Network Segmentation & Isolation 🏰

• Purpose: Restrict network access between services to the bare minimum required. If one service is compromised, it limits the attacker’s ability to move laterally to other services.

• Implementation:

  • Docker Networks: As shown in the docker-compose.yml, place your Supabase services and Caddy on a private Docker network. Do not expose Supabase service ports (PostgREST, GoTrue, etc.) directly to the host or public internet.
  • Host Firewall: Configure your server’s firewall (e.g., ufw on Linux, AWS Security Groups, Google Cloud Firewall Rules) to only allow incoming traffic on ports 80 and 443 (for Caddy) from the public internet. All other ports should be blocked.

  # Example UFW commands
  sudo ufw allow 80/tcp
  sudo ufw allow 443/tcp
  sudo ufw enable

5.6 Secret Management 🤫

• Purpose: Securely store and retrieve sensitive information like database credentials, JWT secrets, API keys, etc.
• Best Practices:
  • Environment Variables: For Docker Compose, pass secrets as environment variables, but ensure they are not committed to version control. Use .env files that are git-ignored.
  • Docker Secrets: For more robust Docker deployments, use Docker Secrets (or Kubernetes Secrets if using K8s).
  • Vault/Dedicated Secret Managers: For very large or complex setups, consider dedicated secret management solutions like HashiCorp Vault.

5.7 Logging & Monitoring 📊

• Purpose: Gain visibility into your API traffic, identify anomalies, and debug issues.
• Implementation:
  • API Gateway Logs: Configure Caddy to log access and errors. You can send logs to stdout (which docker logs will show) or directly to a file.
  • Centralized Logging: For production, forward your logs (from Caddy and all Supabase services) to a centralized logging system (e.g., ELK Stack, Grafana Loki, Splunk, cloud-native logging services like CloudWatch Logs, Stackdriver).
  • Monitoring: Use tools like Prometheus + Grafana to collect metrics (request count, latency, error rates) from your API Gateway and Supabase services. Set up alerts for critical issues.

5.8 DDoS Protection 🚀

• Purpose: Protect against Distributed Denial of Service attacks, which aim to overwhelm your server with a flood of traffic.
• Implementation:
  • Cloudflare: As mentioned, Cloudflare is an excellent choice, offering robust DDoS mitigation, WAF, and caching.
  • Cloud Provider Services: AWS Shield, Azure DDoS Protection, Google Cloud Armor provide similar services for their respective cloud platforms.
  • Rate Limiting: Your API Gateway’s rate limiting is a first line of defense against smaller-scale DoS attempts.

5.9 Regular Updates & Patching 🚨

• Purpose: Vulnerabilities are discovered constantly. Keeping your software up-to-date is paramount for security.
• Best Practices:
  • Regularly update your server’s operating system.
  • Keep Docker and Docker Compose updated.
  • Stay current with the latest Supabase self-hosted releases and Caddy versions. Automate this process where possible, but always test updates in a staging environment first!

6. Advanced Considerations for Scaling & Performance 📈

Once your basic setup is solid, you might consider these advanced topics:

• Load Balancing: If you ever run multiple instances of a Supabase service (e.g., multiple PostgREST replicas for high traffic), your API Gateway can act as a load balancer, distributing requests among them. Caddy’s reverse_proxy directive can handle multiple upstream servers.
• Caching: For static assets or frequently accessed read-only API responses, the API Gateway can implement caching to reduce load on your backend services and improve response times.
• Advanced Observability: Beyond basic logs and metrics, consider distributed tracing to understand the flow of requests across multiple services, especially as your architecture grows.

Conclusion ✨

Self-hosting Supabase offers incredible power and flexibility, but it comes with the responsibility of managing your infrastructure. An API Gateway is not just an add-on; it’s a fundamental part of building a secure, scalable, and maintainable self-hosted Supabase deployment.

By carefully configuring your domains, leveraging automatic HTTPS with tools like Caddy, and implementing robust security measures like rate limiting, WAF, and proper network isolation, you can transform your self-hosted Supabase into a true “security nirvana.” Keep learning, keep optimizing, and enjoy the journey of building your own secure and powerful backend! Happy coding! 💻 securely!