Railway can't establish connection with supabase postgres DB

[pdrbessahm]

Hey guys I've been using supabase for a few days now trying to create the connection between front and backend from my personal project but, long story short, I wasn't able to achieve this.

Since I'm new in the programming world, I'm vibecoding for a lot of complex things (for me) and I've already tried to change my /db.js and also gave it a try to connect using the Database URL.

The answer I got from claude AI after a few tries was:

• Railway is in 'us-west2' thus using IPv6 for supabase;
• Supabase doesn't have IPv6 route;
• Using family: 4 in db.js didn't work given that pg doesn't accept it;

So, in summary I have to use Supabase's Connection Pooler to solve this problem. The AI is asking me to search for pooler's host but I couldn't find it on Supabase. Where exactly should I be looking?

[k1ng-arthur]

I'm not sure what claude is referring to here but the defaut for Supabase is IPV6 https://supabase.com/docs/guides/platform/ipv4-address. I'm not sure if Railway is one of the ones that needs IPV4 but if you head to the connection tab in the dashboard home page you can use different connection strings for your Database including the session pooler for IPv4

[pdrbessahm]

Thanks! I really couldn't find where the pooler connection was even after some researching

[nathanschram]

To add to what @k1ng-arthur said - Railway specifically doesn't support outbound IPv6, which is why the direct connection fails. Supabase's direct connection (db.[ref].supabase.co) only resolves to an IPv6 address, and Railway can't route that.

The session pooler is the right fix. To find it: click the Connect button at the top of your Supabase project dashboard. You should see three options - "Direct connection", "Session pooler", and "Transaction pooler". Grab the Session pooler string - that one routes through pooler.supabase.com which supports IPv4.

It'll look something like:

postgresql://postgres.[your-project-ref]:[your-password]@aws-0-[region].pooler.supabase.com:5432/postgres

One thing to watch - the username for pooler connections is postgres.[your-project-ref] (with a dot and your project ref), not just postgres. The Connect panel fills this in for you though.

Drop that into your db.js and you should be good. You won't need the family: 4 workaround since the pooler hostname resolves to IPv4 natively.

Give that a go and let me know if it sorts it out.

[pdrbessahm]

It's been a while but I gave it a try with @k1ng-arthur's answer. It worked successfully.

I had to change a line in my code though:

const { Pool } = require('pg');

const pool = new Pool({
  host: process.env.DB_HOST,
  port: 5432,
  database: process.env.DB_NAME,
  user: process.env.DB_USER,
  password: process.env.DB_PASSWORD,
  **ssl: { rejectUnauthorized: false },**
});

pool.connect()
  .then(client => {
    console.log('Supabase connected successfully');
    client.release();
  })
  .catch(err => {
    console.error('DB connection failed :', err.message);
    process.exit(1);
  });

pool.on('error', (err) => {
  console.error('Pools unexpected error :', err.message);
});

module.exports = pool;

A few tries before this new solution I had to change the rejectUnauthorized line from true to false. Could this cause any kind of security problems for my web application?

[nathanschram]

Glad the pooler sorted it out!

On the rejectUnauthorized: false question - that disables SSL certificate verification, which means the connection could theoretically be intercepted without you knowing. For local dev it is fine, but for production I would switch it back to true (or just remove the line - true is the default). Supabase pooler has a valid SSL cert so it should work without any issues.

[pdrbessahm]

Thanks!