Heroku Permanent Database Credentials

From Heroku Documentation,

Credentials

Do not copy and paste database credentials to a separate environment or into your application’s code. The database URL is managed by Heroku and will change under some circumstances such as:

• User initiated database credential rotations using heroku pg:credentials:rotate.
• Catastrophic hardware failure leading to Heroku Postgres staff recovering your database on new hardware.
• Automated failover events on HA enabled plans.

It is best practice to always fetch the database URL config var from the corresponding Heroku app when your application starts. For example, you may follow 12Factor application configuration principles by using the Heroku CLI and invoke your process like so:

DATABASE_URL=$(heroku config:get DATABASE_URL -a your-app-name) your_process

This way, you ensure your process or application always has correct database credentials.