How to Set Up & Use System Parameters in Odoo 18

Every growing business eventually faces the need to tweak its ERP system's core behavior without rewriting the source code. Whether it's locking down the base URL for a multi-domain setup or defining a global API timeout threshold, System Parameters in Odoo 18 are your best friend.

In this guide, we'll explore how RetailChain Inc. uses System Parameters to enforce globally consistent password policies and manage their multi-brand e-commerce domains. You'll learn how to create these parameters via the UI and XML, and how to access them dynamically using Python.

Method 1: The User Interface Approach

For quick changes or on-the-fly configuration (like temporarily enabling a maintenance mode flag), the UI is the fastest route.

1. Activate Developer Mode (Settings > General Settings).
2. Navigate to Settings > Technical > Parameters > System Parameters.
3. Click New and define your key-value pair.

Method 2: Defining in Modules (XML)

For permanent configurations that should be deployed across all environments (Staging, Production), define them in your custom module's data file.

<odoo>
  <data noupdate="1">
    <!-- Minimum password length for customer accounts -->
    <record id="auth_signup.password_minlength" model="ir.config_parameter">
      <field name="key">auth_password_minlength</field>
      <field name="value">12</field>
    </record>

    <!-- Custom API Timeout for internal services -->
    <record id="parameter_api_timeout" model="ir.config_parameter">
      <field name="key">retail.internal_api_timeout</field>
      <field name="value">30</field>
    </record>
  </data>
</odoo>

Accessing Parameters in Python

Once your parameters are set, you need to use them in your business logic. Here is how you can retrieve and update them programmatically.

def check_discount_policy(self):
    # Retrieve the parameter
    # NOTE: get_param ALWAYS returns a string!
    limit_str = self.env['ir.config_parameter'].sudo().get_param('retail.global_discount_limit', default='0')
    
    # Always cast the type safely
    limit = float(limit_str)

    if self.discount > limit:
        raise ValidationError(f"Discount cannot exceed global limit of {limit}%")

def set_new_timeout(self, seconds):
    # Update or create a parameter
    self.env['ir.config_parameter'].sudo().set_param('retail.internal_api_timeout', str(seconds))

Critical Tip: Freezing the URL

Odoo automatically updates the web.base.url parameter based on the administrator's latest login domain. In production, this can break email links if an admin logs in via a localhost tunnel or an internal IP.

To prevent this, enable the "Freeze" parameter:

Conclusion

System parameters separate your configuration from your code, making your Odoo modules cleaner, more portable, and easier to manage across different environments. Whether you are enforcing security policies or managing global variables for RetailChain Inc., mastering ir.config_parameter is a fundamental skill for any Odoo developer.