> ## Documentation Index
> Fetch the complete documentation index at: https://docs.usecharlie.ai/llms.txt
> Use this file to discover all available pages before exploring further.
# Product Rules
> Prioritize fulfillment locations based on what products are in the cart
Product rules let you prioritize locations based on **what's in the cart**. When a customer orders specific products, you can control which locations should be preferred for fulfillment.
Unlike [fulfillment constraints](/constraints/product-rules) which **block** locations, product routing rules **prioritize** locations. If the preferred location is out of stock, Shopify automatically falls back to the next available location.
## Constraints vs Routing
| | Fulfillment Constraints | Order Routing Rules |
| ------------------------------------- | ------------------------------------------------ | ---------------------------------------------------------------- |
| **Effect** | Blocks locations entirely | Ranks locations by preference |
| **If no stock at preferred location** | Checkout blocked | Falls back to next priority |
| **Configured in** | Charlie app | Shopify Order Routing settings |
| **Use case** | "Fragile items can NEVER ship from small stores" | "Prefer warehouse for fragile items, but allow stores as backup" |
## How product routing rules work
A product routing rule has two parts:
1. **When** (condition): Which products trigger the rule
2. **Then** (groups): How to rank locations when triggered
```mermaid theme={"system"}
flowchart LR
A[Customer adds
product to cart] --> B{Product matches
rule condition?}
B -->|No| C[Default routing
applies]
B -->|Yes| D[Apply location
group ranking]
D --> E[Try Group 1 first]
E --> F{Stock
available?}
F -->|Yes| G[✅ Fulfill from Group 1]
F -->|No| H[Try Group 2]
H --> I[Continue to next group...]
```
## Configure a product routing rule
Go to **Charlie → Settings → Order routing** or **Shopify → Settings → Shipping and delivery → Order routing**.
Find Charlie's **Product Rules** and add it to your routing strategy.
Set up which products trigger this rule:
| Field | Options |
| ------------- | ----------------------------- |
| **Condition** | Product is |
| **Operator** | Is one of / Is not one of |
| **Value** | Enter one or more product IDs |
Create ranked groups of locations. Group 1 has highest priority, Group 2 is the fallback, and so on.
For each group, click **Add selector** and choose how to select locations:
| Selector type | Description |
| ---------------------- | ------------------------------------ |
| **Specific locations** | Choose individual locations manually |
| **Location type** | All Warehouses or all Stores |
| **Location tag** | Locations with specific tags |
Locations that don't match any group will be ranked last, as shown in the interface: "All locations that do not match any of the groups will be ranked last."
Toggle the rule to **Enabled** when you're ready to apply it to live orders.
## Condition options
Rule triggers when the cart contains **any** of the specified products.
**Example:** Cart contains Product A OR Product B → Apply ranking
**Use case:** Premium products that should prefer flagship stores.
Rule triggers when the cart does **not** contain the specified products.
**Example:** Cart does NOT contain Product A → Apply ranking
**Use case:** Route standard products away from specialty locations.
## Examples
### Premium products prefer flagship stores
A fashion brand wants premium items to be fulfilled from flagship stores when possible, with warehouses as backup.
Get the product IDs for your premium items from Shopify.
* **Condition:** Product is
* **Operator:** Is one of
* **Value:** \[Premium product IDs]
* **Group 1:** Location tag = `flagship`
* **Group 2:** Location type = Warehouse
* **Group 3:** Location type = Store
**Result:** Premium products prefer flagship stores first. If out of stock, warehouses are tried, then other stores. No checkout blocking.
***
### Heavy items prefer warehouse
A furniture retailer wants heavy items to ship from warehouses with freight capabilities, but allows store fulfillment as backup.
Add the tag `freight-capable` to warehouses with shipping equipment.
* **Condition:** Product is
* **Operator:** Is one of
* **Value:** \[Heavy furniture product IDs]
* **Group 1:** Location tag = `freight-capable`
* **Group 2:** Location type = Warehouse
* **Group 3:** Location type = Store
**Result:** Heavy items prefer freight-capable locations, but can still be fulfilled from stores if needed.
***
### Standard products avoid specialty locations
Keep specialty locations (like those with engraving equipment) available for orders that need them.
Get the product IDs for items that require specialty equipment.
* **Condition:** Product is
* **Operator:** Is not one of
* **Value:** \[Specialty product IDs]
* **Group 1:** Location type = Warehouse
* **Group 2:** Location tag = `standard-store`
* **Group 3:** Location tag = `specialty`
**Result:** Standard products try warehouses and regular stores first, leaving specialty locations available for products that need them.
## Combining with constraints
For maximum control, combine routing rules with constraints:
| Rule type | Purpose |
| ---------------- | ---------------------------------------------- |
| **Constraint** | Block locations that absolutely cannot fulfill |
| **Routing rule** | Prioritize among remaining eligible locations |
**Example: Fragile items strategy**
1. **Fulfillment Constraint:** Exclude locations tagged `no-fragile-handling` → Small stores are **blocked**
2. **Product Routing Rule:** Prefer locations tagged `fragile-certified` → Certified locations are **preferred**, but others can still fulfill
**Result:** Fragile items never ship from incapable locations (constraint), and prefer specialized locations when available (routing).
## Best practices
Use routing rules when you have preferences but can accept alternatives. Reserve constraints for hard requirements.
Instead of listing individual products, consider using collections in your constraint rules and product tags for common patterns.
Product rules work well with Inventory Rules (prefer locations with more stock of the specific product).
Verify your routing with test orders before high-volume periods.
## Troubleshooting
**Check:**
1. Is the rule **enabled**?
2. Are the product IDs correct? (Check in Shopify Admin → Products)
3. Does the preferred location have stock?
4. Are there constraint rules blocking the location?
5. Is another routing rule with higher priority overriding this one?
**Check:**
1. Is the operator correct? ("Is one of" vs "Is not one of")
2. Are the product IDs in the correct format?
3. Is the rule placed correctly in the routing order?
Remember: Shopify tries groups in order and uses the first one with available stock. If Group 1 is out of stock, it moves to Group 2 automatically.
Verify stock levels at each location for the products in question.
## Related
Block locations based on products (hard rules)
Create default location priorities
Prioritize by stock availability
Set up tags for flexible grouping