Why is SQLAlchemy 1.4.x not connecting to Heroku Postgres?


When using SQLAlchemy 1.4.x to connect to Heroku Postgres, I receive the following error:

sqlalchemy.exc.NoSuchModuleError: Can't load plugin: sqlalchemy.dialects:postgres


SQLAlchemy 1.4.x has removed support for the postgres:// URI scheme, which is used by Heroku Postgres (https://github.com/sqlalchemy/sqlalchemy/issues/6083). To maintain compatibility, perform the following before setting up connections with SQLAlchemy:

import os

uri = os.getenv("DATABASE_URL")  # or other relevant config var
if uri.startswith("postgres://"):
    uri = uri.replace("postgres://", "postgresql://", 1)
# rest of connection code using the connection string `uri`

This will allow you to connect to Heroku Postgres services using SQLAlchemy >= 1.4.x

Ask on Stack Overflow

Engage with a community of passionate experts to get the answers you need

Ask on Stack Overflow

Heroku Support

Create a support ticket and our support experts will get back to you

Contact Heroku Support