Quick Answer
Stop paying $8,000-$40,000 for consultants to build custom Odoo modules. Build your own in 40-80 hours for simple modules. Learn models (database tables), fields (data types), views (UI), and actions (navigation). Save $50,000-$200,000/year in consulting costs. You own it, modify it, understand it.
Your Options for Custom Functionality
You're running a $2M D2C brand on Odoo. The base system handles orders, inventory, and accounting. But you have unique workflows that Odoo doesn't support out-of-the-box.
| Option | Cost | Timeline | Problem |
|---|---|---|---|
| A: Buy App | $800-$3,000/year per app | Immediate | Exact workflow doesn't exist, need 3 apps |
| B: Hire Consultant | $8,000-$40,000 | 4-12 weeks | Dependent on consultant, updates expensive |
| C: Build Your Own | $0 (time only) | 40-80 hours | You own it, modify it, understand it |
We've implemented 150+ Odoo systems. The brands that learned to build simple custom modules? They're shipping updates monthly. They're adapting Odoo to their processes without waiting for consultants. They're saving $50,000-$200,000/year in consulting costs.
The Reality of Odoo Module Development
Myth vs. Reality
❌ Myth #1: "You need to be an expert Python developer"
✓ Reality: You need basic Python. If you understand loops, variables, and functions, you can build an Odoo module. The hard part isn't coding—it's understanding Odoo's architecture.
❌ Myth #2: "It takes months to build a simple module"
✓ Reality: A simple module takes 40-80 hours. A medium module takes 2-4 weeks. A complex system takes 2-3 months.
❌ Myth #3: "You need to understand the entire Odoo codebase"
✓ Reality: You need to understand models (database tables), fields (data types), views (UI), and actions/menus (navigation). That's 80% of what you need.
❌ Myth #4: "Custom modules break with updates"
✓ Reality: If built properly (following Odoo conventions), custom modules survive updates. The key is not modifying core Odoo code—you extend it.
The Real-World Problem (Our First Module)
You're a D2C fashion brand tracking inventory across Shopify, Amazon, and your warehouse. When inventory drops below a threshold, you need to:
1. Flag the product as "low stock"
2. Notify the procurement team
3. Track when you ordered more
4. Measure reorder-to-replenish time (how fast can we restock?)
Odoo's native inventory module does (1). It doesn't do (2), (3), or (4).
So you build a custom module called inventory_alerts.
Cost to build: $0. Timeline: 60 hours. Value delivered: $40,000/year (hours saved not managing reorders manually).
Step 1: Create the Module Folder Structure
Navigate to your Odoo addons directory and create a folder:
inventory_alerts/
├── __init__.py
├── __manifest__.py
├── models/
│ ├── __init__.py
│ └── low_stock_alert.py
├── views/
│ ├── __init__.py
│ └── low_stock_alert_views.xml
├── security/
│ └── ir.model.access.csv
└── static/
└── description/
└── icon.pngThis is the standard Odoo module structure. Every module follows this pattern.
Step 2: Create the Manifest File
{
'name': 'Low Stock Alerts',
'version': '18.0.1.0.0',
'category': 'Inventory',
'summary': 'Alert on low inventory levels and track reorder cycles',
'description': '''
Tracks when products hit low stock threshold.
Notifies team and measures reorder-to-replenish cycle time.
''',
'author': 'Your Company',
'license': 'AGPL-3',
'depends': ['inventory', 'mail'], # Depends on Inventory module and Mail
'data': [
'security/ir.model.access.csv', # Security permissions
'views/low_stock_alert_views.xml', # User interface
],
'installable': True,
'application': False,
}Step 3: Create the Data Model
The model is the database table. It defines what data your module stores.
from odoo import models, fields, api
from datetime import datetime
class LowStockAlert(models.Model):
"""
Model to track low stock alerts for products.
"""
_name = 'low.stock.alert'
_description = 'Low Stock Alert'
_order = 'date_alert DESC'
# FIELDS (columns in database table)
product_id = fields.Many2one(
'product.product',
string='Product',
required=True,
help='Product that triggered the alert'
)
warehouse_id = fields.Many2one(
'stock.warehouse',
string='Warehouse',
required=True,
help='Warehouse where stock is low'
)
current_stock = fields.Float(
string='Current Stock',
help='Stock level when alert was triggered'
)
low_stock_threshold = fields.Float(
string='Low Stock Threshold',
required=True,
default=10,
help='Stock level below which alert triggers'
)
date_alert = fields.Datetime(
string='Alert Date',
default=fields.Datetime.now,
help='When the alert was created'
)
date_order_placed = fields.Datetime(
string='Order Placed Date',
help='When we ordered more stock'
)
date_replenished = fields.Datetime(
string='Replenish Date',
help='When stock arrived and was replenished'
)
state = fields.Selection(
[
('alert', 'Alert Triggered'),
('ordered', 'Order Placed'),
('replenished', 'Replenished'),
],
string='Status',
default='alert',
help='Current state of the alert lifecycle'
)
reorder_cycle_days = fields.Float(
string='Reorder-to-Replenish (days)',
compute='_compute_reorder_cycle',
store=True,
help='Days from alert to replenishment'
)
notes = fields.Text(
string='Notes',
help='Additional notes about this alert'
)
@api.depends('date_alert', 'date_replenished')
def _compute_reorder_cycle(self):
for record in self:
if record.date_alert and record.date_replenished:
delta = record.date_replenished - record.date_alert
record.reorder_cycle_days = delta.days
else:
record.reorder_cycle_days = 0Step 4: Create the Views
Views define how users see and interact with your data.
<?xml version="1.0" encoding="utf-8"?>
<odoo>
<!-- FORM VIEW -->
<record id="view_low_stock_alert_form" model="ir.ui.view">
<field name="name">Low Stock Alert Form</field>
<field name="model">low.stock.alert</field>
<field name="arch" type="xml">
<form>
<header>
<field name="state" widget="statusbar"
statusbar_visible="alert,ordered,replenished"/>
</header>
<sheet>
<group>
<field name="product_id"/>
<field name="warehouse_id"/>
</group>
<group string="Stock Information">
<field name="current_stock"/>
<field name="low_stock_threshold"/>
</group>
<group string="Reorder Timeline">
<field name="date_alert"/>
<field name="date_order_placed"/>
<field name="date_replenished"/>
<field name="reorder_cycle_days"/>
</group>
<group>
<field name="notes" nolabel="1" colspan="2"/>
</group>
</sheet>
</form>
</field>
</record>
<!-- LIST VIEW -->
<record id="view_low_stock_alert_list" model="ir.ui.view">
<field name="name">Low Stock Alert List</field>
<field name="model">low.stock.alert</field>
<field name="arch" type="xml">
<tree>
<field name="product_id"/>
<field name="warehouse_id"/>
<field name="current_stock"/>
<field name="low_stock_threshold"/>
<field name="state"/>
<field name="date_alert"/>
</tree>
</field>
</record>
<!-- ACTION -->
<record id="action_low_stock_alert" model="ir.actions.act_window">
<field name="name">Low Stock Alerts</field>
<field name="res_model">low.stock.alert</field>
<field name="view_mode">tree,form</field>
</record>
<!-- MENU ITEM -->
<menuitem id="menu_low_stock_alert"
name="Low Stock Alerts"
parent="stock.menu_stock_root"
action="action_low_stock_alert"
sequence="10"/>
</odoo>Step 5: Create Security Permissions
id,name,model_id:id,group_id:id,perm_read,perm_write,perm_create,perm_unlink
access_low_stock_alert_user,Low Stock Alert - User,model_low_stock_alert,stock.group_stock_user,1,1,1,0
access_low_stock_alert_manager,Low Stock Alert - Manager,model_low_stock_alert,stock.group_stock_manager,1,1,1,1Step 6: Create __init__.py Files
from . import modelsfrom . import low_stock_alertStep 7: Install and Test Your Module
sudo systemctl restart odoo1. Navigate to Apps in Odoo
2. Click "Update Apps List"
3. Search for "Low Stock Alerts"
4. Click Install
Add Automation (Cron Jobs)
Make alerts create automatically when inventory drops below threshold.
<?xml version="1.0" encoding="utf-8"?>
<odoo>
<record id="cron_check_low_stock" model="ir.cron">
<field name="name">Check Low Stock Levels</field>
<field name="model_id" ref="model_low_stock_alert"/>
<field name="state">code</field>
<field name="code">model.env['low.stock.alert']._check_low_stock()</field>
<field name="interval_number">1</field>
<field name="interval_type">days</field>
<field name="numbercall">-1</field>
<field name="doall" eval="True"/>
</record>
</odoo>Complete Module Cost-Benefit Analysis
| Metric | Build Your Own | Hire Consultant |
|---|---|---|
| Time | 60 hours | 4-12 weeks |
| Cost | $3,000 | $8,000-$40,000 |
| Annual Value | $50,000+ | $50,000+ |
| Year 1 ROI | $47,000 | $10,000-$42,000 |
Action Items: Build Your Module
Week 1: Build the Module
❏ Create folder structure (30 min)
❏ Create manifest file (30 min)
❏ Create model with fields (2 hours)
❏ Create views (2 hours)
❏ Create security (30 min)
❏ Install and test (1 hour)
Week 2: Add Automation
❏ Add cron job (2 hours)
❏ Test automatic alert creation (1 hour)
❏ Deploy to production (30 min)
Frequently Asked Questions
Do I need to be an expert Python developer to build Odoo modules?
No. You need basic Python (loops, variables, functions). The hard part isn't coding—it's understanding Odoo's architecture: models (database tables), fields (data types), views (UI), and actions (navigation). That's 80% of what you need.
How long does it take to build a simple Odoo module?
A simple module takes 40-80 hours. A medium module takes 2-4 weeks. A complex system takes 2-3 months. The timeline scales with complexity, not some mysterious factor.
Will my custom module break when Odoo updates?
No, if built properly. Follow Odoo conventions and don't modify core Odoo code—extend it using _inherit. Custom modules that follow best practices survive updates without breaking.
How much can I save by building modules myself vs. hiring consultants?
Build yourself: $3,000 (60 hours). Hire consultant: $8,000-$40,000. Savings: $5,000-$37,000 per module. Brands that learn to build modules save $50,000-$200,000/year in consulting costs.
Free Custom Module Development Workshop
Stop paying for consulting when you can build it yourself. We'll assess your most pressing workflow problems, design a custom module that solves it, walk you through building it, provide an architecture review of your code, and set you up for long-term maintenance. Most D2C brands spend $40,000+/year on custom development that costs $3,000 to build in-house. Learning to build modules is a 20x return on investment.