In Fire, a COMBO is a product whose price is not fixed in the catalog — it depends on which options the customer selects across its required modifier groups. When you receive a COMBO in a menu.updated event, priceInfo.price is always 0. This is intentional. Fire pre-computes the minimum reachable price and stores it in priceInfo.referencePrice.
Identifying a COMBO in the payload
Look for "type": "COMBO" in data.menu.products:
{
"productId": "combo_001",
"name": "Box da Torcida",
"type": "COMBO",
"priceInfo": {
"price": 0,
"referencePrice": 9990
},
"productModifiers": [
{
"modifierId": "mod_box",
"position": 1,
"overrides": [
{
"productId": "prod_tiras_6",
"priceInfo": {
"price": 3800,
"referencePrice": 3800
}
}
]
}
]
}
Never display priceInfo.price for a COMBO — it is always 0. Use priceInfo.referencePrice as the header price.
Modifier overrides
A product can appear in many combos and many menus. In the global products[] list it has a single base price. But when that product acts as a modifier option inside a specific combo, its price within that combo may differ — for example, a medium fries that sells for R8.00individuallymightcostR 6.40 when bundled in a particular combo.
That is what productModifiers[n].overrides is for: it lets each combo declare a different price for any of its modifier options without changing the product’s base catalog price.
Structure
Each entry in overrides targets one modifier option by its productId:
"productModifiers": [
{
"modifierId": "mod_fries",
"position": 2,
"overrides": [
{
"productId": "prod_fries_medium",
"priceInfo": {
"price": 640,
"referencePrice": 640
}
},
{
"productId": "prod_fries_large",
"priceInfo": {
"price": 830,
"referencePrice": 830
}
}
]
}
]
prod_fries_medium has a base price of R8.00in‘products[]‘,buttheoverridesetsittoR 6.40 for this combo. prod_fries_large is similarly overridden to R$ 8.30.
Resolving the effective price
When processing a modifier option, always check overrides first:
effective_price = override.priceInfo.price // if an override exists for this productId
?? option_product.priceInfo.price // otherwise: option's own price in products[]
Reference price
priceInfo.referencePrice is pre-computed by Fire as the minimum the customer can pay for the combo:
for each required modifier group (minOptions ≥ 1):
baseline = cheapest effective price among the group's options
subtotal = baseline × minOptions
referencePrice = sum of all subtotals
priceInfo.price for display.
Worked example — Box da Torcida
| Modifier group | minOptions | Cheapest option (effective) | Subtotal |
|---|
| Choose your box | 1 | R$ 31.00 — 12 Coxinhas | R$ 31.00 |
| Choose your fries | 2 | R$ 6.40 — Medium fries | R$ 12.80 |
| Choose your sauce | 2 | R$ 5.70 — any sauce | R$ 11.40 |
| Choose your drink | 3 | R$ 14.90 — 400 ml | R$ 44.70 |
| Reference total | | | R$ 99.90 |
Customer-facing display logic
Show prices relative to the cheapest option in the group — not the absolute catalog price. This way customers see what a premium option costs on top of the base selection.
baseline = min effective_price across all options in the group
delta = max(0, effective_price − baseline)
| delta | Display |
|---|
0 | ”Included” or no label — this is the base option |
> 0 | +R$ X.XX |
minOptions ≥ 1). For optional groups (minOptions = 0), show the full add-on price for each option.
Example — Choose your box (required, pick 1)
| Option | Effective price | Baseline | Displayed |
|---|
| 12 Coxinhas | R$ 31.00 | R$ 31.00 | Included |
| 8 Tiras | R$ 38.00 | R$ 31.00 | +R$ 7.00 |
| 6 Tiras | R$ 41.00 | R$ 31.00 | +R$ 10.00 |
prod_tiras_6 (R$ 38.00) is used instead of its base catalog price.
Example — Choose your sauce (required, all same price)
| Option | Effective price | Baseline | Displayed |
|---|
| Honey mustard | R$ 5.70 | R$ 5.70 | Included |
| BBQ | R$ 5.70 | R$ 5.70 | Included |
| Ketchup | R$ 5.70 | R$ 5.70 | Included |
Cart total
The total displayed on the “Add to order” button updates live as the customer makes selections:
cart_total = (referencePrice + sum of selected deltas) × quantity
referencePrice. 
