Delivery Cost Calculator Development
Delivery calculator must give accurate answer before checkout—not "from 300 rubles," but exact amount with delivery method and date selection. Vague checkout phrasing directly causes cart abandonment. Baymard Institute data shows unexpected delivery cost is the reason for abandoned cart in 48% of cases.
Architecture
Request (city + items + weight) → DeliveryCalculator → [Carrier APIs] → Option List → Frontend
Calculator works both on product pages (approximate) and in cart (exact, accounting for full composition).
Data Schema
CREATE TABLE delivery_zones (
id BIGSERIAL PRIMARY KEY,
name VARCHAR(255),
country CHAR(2) DEFAULT 'RU',
regions TEXT[], -- FIAS region codes
cities TEXT[], -- KLADR city codes
carrier_id INT REFERENCES carriers(id)
);
CREATE TABLE delivery_rates (
id BIGSERIAL PRIMARY KEY,
carrier_id INT REFERENCES carriers(id),
zone_id BIGINT REFERENCES delivery_zones(id),
method VARCHAR(50), -- 'courier', 'pickup', 'post'
weight_from_g INT DEFAULT 0,
weight_to_g INT,
price NUMERIC(10,2) NOT NULL,
days_min SMALLINT,
days_max SMALLINT,
free_from NUMERIC(12,2), -- free when sum >= X
is_active BOOLEAN DEFAULT TRUE
);
Calculation Service
class DeliveryCalculatorService
{
public function calculate(DeliveryRequest $request): DeliveryResult
{
$totalWeight = $this->calculateWeight($request->items);
$totalPrice = $request->items->sum(fn($i) => $i->price * $i->quantity);
$zone = $this->zoneResolver->resolve($request->destination);
if (!$zone) {
return $this->calculateViaApi($request, $totalWeight, $totalPrice);
}
$rates = DeliveryRate::where('zone_id', $zone->id)
->where('weight_from_g', '<=', $totalWeight)
->where(fn($q) => $q->whereNull('weight_to_g')->orWhere('weight_to_g', '>=', $totalWeight))
->where('is_active', true)
->with('carrier')
->orderBy('price')
->get();
$options = $rates->map(function ($rate) use ($totalPrice) {
$price = ($rate->free_from && $totalPrice >= $rate->free_from) ? 0 : $rate->price;
return new DeliveryOption(
carrierId: $rate->carrier_id,
method: $rate->method,
name: $rate->carrier->name . ' — ' . $rate->method_label,
price: $price,
daysMin: $rate->days_min,
daysMax: $rate->days_max,
isFree: $price === 0.0,
);
});
return new DeliveryResult(options: $options, destination: $request->destination);
}
private function calculateWeight(Collection $items): int
{
return $items->sum(function ($item) {
$product = $item->product;
$weight = $product->weight_g ?? 500; // default 500g if not specified
return $weight * $item->quantity;
});
}
}
CDEK API Integration
class CdekDeliveryProvider implements DeliveryProviderInterface
{
private string $baseUrl = 'https://api.cdek.ru/v2';
public function calculate(DeliveryRequest $request, int $weightG): array
{
$token = $this->getToken();
$response = Http::withToken($token)
->post("{$this->baseUrl}/calculator/tarifflist", [
'type' => 1, // 1 = e-commerce
'currency' => 1, // RUB
'lang' => 'eng',
'from_location' => ['code' => config('cdek.from_city_code')],
'to_location' => ['address' => $request->destination->address],
'packages' => [[
'weight' => $weightG,
'length' => 30,
'width' => 20,
'height' => 10,
]],
]);
if (!$response->successful()) return [];
return collect($response->json('tariff_codes', []))
->map(fn($t) => new DeliveryOption(
carrierId: 'cdek',
method: $this->mapTariffToMethod($t['tariff_code']),
name: 'CDEK — ' . $t['tariff_name'],
price: $t['delivery_sum'],
daysMin: $t['period_min'],
daysMax: $t['period_max'],
))
->toArray();
}
private function getToken(): string
{
return Cache::remember('cdek_token', 3600, function () {
$response = Http::post("{$this->baseUrl}/oauth/token", [
'grant_type' => 'client_credentials',
'client_id' => config('cdek.client_id'),
'client_secret' => config('cdek.client_secret'),
]);
return $response->json('access_token');
});
}
}
Russian Post Integration
class RussianPostProvider implements DeliveryProviderInterface
{
public function calculate(DeliveryRequest $request, int $weightG): array
{
$response = Http::withHeaders([
'Authorization' => 'AccessToken ' . config('russianpost.token'),
'X-User-Login' => config('russianpost.login'),
'Content-Type' => 'application/json',
])->post('https://tariff.pochta.ru/v2/calculate/tariff', [
'object' => 47020, // PARCEL ONLINE
'from' => config('russianpost.from_index'),
'to' => $request->destination->postalCode,
'weight' => $weightG,
'fragile' => false,
'declared' => (int) ($request->declaredValue * 100), // in kopeks
]);
if (!$response->successful()) return [];
$total = $response->json('paymoney', 0) / 100;
return [new DeliveryOption(
carrierId: 'russianpost',
method: 'post',
name: 'Russian Post',
price: $total,
daysMin: $response->json('delivery.min') ?? 7,
daysMax: $response->json('delivery.max') ?? 14,
)];
}
}
API Endpoint for Frontend
class DeliveryCalculatorController extends Controller
{
public function calculate(CalculateRequest $request): JsonResponse
{
$cacheKey = 'delivery.' . md5(serialize($request->validated()));
$result = Cache::remember($cacheKey, 300, function () use ($request) {
return $this->calculator->calculate(
DeliveryRequest::fromArray($request->validated())
);
});
return response()->json([
'options' => DeliveryOptionResource::collection($result->options),
'destination' => $result->destination->label,
]);
}
}
Frontend Component
const DeliveryCalculator: React.FC<{ cartItems: CartItem[] }> = ({ cartItems }) => {
const [city, setCity] = useState('');
const [options, setOptions] = useState<DeliveryOption[]>([]);
const [loading, setLoading] = useState(false);
const calculate = useDebouncedCallback(async (cityValue: string) => {
if (cityValue.length < 3) return;
setLoading(true);
try {
const res = await api.post('/delivery/calculate', {
destination: cityValue,
items: cartItems.map(i => ({ product_id: i.id, quantity: i.qty })),
});
setOptions(res.data.options);
} finally {
setLoading(false);
}
}, 600);
return (
<div>
<input
placeholder="Enter delivery city"
value={city}
onChange={e => { setCity(e.target.value); calculate(e.target.value); }}
className="border rounded px-3 py-2 w-full"
/>
{loading && <p className="text-sm text-gray-400 mt-2">Calculating...</p>}
{options.length > 0 && (
<ul className="mt-3 space-y-2">
{options.map(opt => (
<li key={opt.id} className="flex justify-between items-center border rounded px-3 py-2">
<div>
<p className="font-medium">{opt.name}</p>
<p className="text-sm text-gray-500">{opt.daysMin}–{opt.daysMax} days</p>
</div>
<span className="font-semibold">
{opt.isFree ? 'Free' : formatPrice(opt.price)}
</span>
</li>
))}
</ul>
)}
</div>
);
};
City Hints via DaData
const [suggestions, setSuggestions] = useState<string[]>([]);
const fetchCities = useDebouncedCallback(async (query: string) => {
const res = await fetch('https://suggestions.dadata.ru/suggestions/api/4_1/rs/suggest/address', {
method: 'POST',
headers: {
'Content-Type': 'application/json',
'Authorization': `Token ${DADATA_TOKEN}`,
},
body: JSON.stringify({ query, from_bound: { value: 'city' }, to_bound: { value: 'city' }, count: 5 }),
});
const data = await res.json();
setSuggestions(data.suggestions.map((s: any) => s.value));
}, 400);
Timeline
- Data schema + DeliveryCalculatorService + zones table: 1 day
- CDEK API: 1 day
- Russian Post API: 0.5 days
- Frontend component + city hints: 1 day
- Caching + API endpoint: 0.5 days
Total: 3–4 working days.