> ## Documentation Index
> Fetch the complete documentation index at: https://docs.layerrail.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Connect to PostgreSQL

> Connect applications, psql, and database tools to a LayerRail PostgreSQL database using connection strings, TLS, and connection pooling.

The database connection page contains the host, port, username, database name, and connection string for your PostgreSQL instance.

## Connection string

A PostgreSQL connection string usually looks like this:

```bash theme={null}
postgresql://<user>:<password>@<host>:5432/<database>?sslmode=require
```

Set it as an environment variable in your application:

```bash theme={null}
export DATABASE_URL="postgresql://<user>:<password>@<host>:5432/<database>?sslmode=require"
```

## Test with psql

```bash theme={null}
psql "$DATABASE_URL"
```

Run a simple query:

```sql theme={null}
select version();
```

## TLS

Use TLS for application connections. If your framework supports `sslmode=require`, keep it enabled in production.

```bash theme={null}
postgresql://<user>:<password>@<host>:5432/<database>?sslmode=require
```

## Application examples

<Tabs>
  <Tab title="Node.js">
    ```js theme={null}
    import pg from "pg";

    const pool = new pg.Pool({
      connectionString: process.env.DATABASE_URL,
      ssl: { rejectUnauthorized: false }
    });
    ```
  </Tab>

  <Tab title="Ruby">
    ```ruby theme={null}
    require "pg"

    conn = PG.connect(ENV.fetch("DATABASE_URL"))
    puts conn.exec("select now()").first
    ```
  </Tab>

  <Tab title="Python">
    ```python theme={null}
    import os
    import psycopg

    with psycopg.connect(os.environ["DATABASE_URL"]) as conn:
        print(conn.execute("select now()").fetchone())
    ```
  </Tab>
</Tabs>

<Warning>
  Treat database passwords like secrets. Do not commit connection strings to Git.
</Warning>