Connecting Services

Services within a Stackpad project communicate over a private Docker network using simple DNS names. No IP addresses, no external URLs, no configuration — just use the service name as the hostname.

How it works

When you create a project, Stackpad creates an isolated Docker network for that project. Every service in the project is attached to this network and gets a DNS alias matching its name.

For example, if your project has:

• A web service called web
• A PostgreSQL service called postgres
• A Redis service called redis

Then from your web service, you can connect to:

Service	Hostname	Port
PostgreSQL	postgres	5432
Redis	redis	6379
Another web service	api	3000

// Connect to PostgreSQL
const db = new Pool({ host: 'postgres', port: 5432 });

// Connect to Redis
const redis = new Redis({ host: 'redis', port: 6379 });

// Call another service
const response = await fetch('http://api:3000/health');

Automatic credential injection

For database and cache services, Stackpad goes a step further — it automatically generates credentials and injects connection strings into your web services:

Service type	Environment variable
PostgreSQL	DATABASE_URL=postgresql://user:pass@postgres:5432/db
MariaDB	MYSQL_URL=mysql://user:pass@mariadb:3306/db
Redis	REDIS_URL=redis://redis:6379
Valkey	REDIS_URL=redis://valkey:6379

Your application just reads process.env.DATABASE_URL and it works.

Network isolation

Each project has its own isolated network. Services from different projects cannot communicate with each other. This ensures:

• Security — no cross-project data leaks
• DNS isolation — postgres in project A resolves to a different container than postgres in project B
• Performance — no noisy-neighbor effects on network traffic

Public access

By default, only web services are exposed externally via HTTPS. Databases and caches are only accessible from within the project’s private network.

If you need to connect from outside Stackpad (e.g. your local machine, an external tool, or a CI pipeline), you can enable public access per service:

1. Go to the service Settings tab
2. Toggle Public access on
3. A connection string with the public endpoint appears

Encrypted public access

All public connections are TLS-encrypted and use standard ports:

Service type	Port	TLS parameter
PostgreSQL	5432	sslmode=require
MySQL / MariaDB	3306	ssl=true
Redis / Valkey	6379	ssl=true
MongoDB	27017	tls=true

The public hostname follows the format {serviceId}.db.stackpad.eu. Connection strings include full credentials — copy and paste into TablePlus, pgAdmin, Redis Insight, or your application.

postgresql://user:pass@abc123.db.stackpad.eu:5432/db?sslmode=require

Caution

Only enable public access when you need it. While connections are password-protected and TLS-encrypted, reducing exposure is a security best practice.

What’s next?

• PostgreSQL — add a database to your project
• Redis & Valkey — add caching to your project
• PgBouncer — connection pooling for PostgreSQL
• Networking concepts — deep dive into the networking architecture