nkscoder-courier 1.1.1

Django zone-based courier shipping cost calculator — by Nitesh Kumar Singh (nkscoder)

Courier — Generic Django Zone-Based Shipping Cost Calculator

Author: Nitesh Kumar Singh · GitHub: @nkscoder

A generic, reusable Django courier app for calculating zone-based shipping costs by weight, quantity, and destination. Works out of the box with built-in country/region models, or plugs into your existing location tables. Built by Nitesh Kumar Singh (nkscoder).

Keywords: django courier · generic shipping calculator · zone-based shipping · weight pricing · reusable django app · nkscoder · nitesh kumar singh · python shipping

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Features

• Generic by design — built-in CourierCountry / CourierRegion models, no core app required
• Configurable pricing — domestic multiplier, international surcharge %, weight units, thresholds
• Zone-based pricing — map countries and regions to shipping zones
• Weight slab lookup — automatic cost lookup by weight brackets
• Multi-unit support — grams, kilograms, and pounds (gram, kgs, lbs)
• JSON API endpoint — real-time shipping quotes via HTTP GET
• Python API — call calculate_courier_cost() from checkout, cart, or background jobs
• Custom zone resolver — plug in your own location models with one settings hook
• Django Admin — manage countries, regions, zones, and weight costs

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Requirements

• Python 3.8–3.12 (including 3.12)
• Django 3.2+

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Installation

pip install nkscoder-courier

With Django Admin CSV import/export:

pip install "nkscoder-courier[admin]"

From GitHub:

pip install git+https://github.com/nkscoder/courier.git

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Quick start

# settings.py
INSTALLED_APPS = [
    ...
    "courier",
]

COURIER_DOMESTIC_COUNTRY_NAME = "India"
COURIER_INTERNATIONAL_SURCHARGE_PERCENT = 22

python manage.py migrate courier

# urls.py
urlpatterns = [
    path("courier/", include("courier.urls")),
]

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Usage

Python API (recommended)

from courier.calculator import calculate_courier_cost

total = calculate_courier_cost(
    weight=1.5,
    quantity=2,
    weight_unit="kgs",
    country_id=country.pk,
    region_id=region.pk,  # optional for domestic regions
)

Backward-compatible alias:

from courier import courier_cost

total = courier_cost(weight=500, quantity=1, weight_unit="gram", country=1, state=3)

HTTP API

GET /courier/?weight=500&quantity=2&weight_unit=gram&country=1&region=3

Response:

{"total": 150}

Parameter	Description
weight	Package weight
quantity	Number of packages
weight_unit	gram, kgs, or lbs
country	Country PK
region or state	Region PK (for domestic destinations)

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Configuration

All settings use the COURIER_ prefix:

Setting	Default	Description
COURIER_COUNTRY_MODEL	courier.CourierCountry	Country model label
COURIER_REGION_MODEL	courier.CourierRegion	Region/state model label
COURIER_DOMESTIC_COUNTRY_NAME	India	Fallback domestic country name
COURIER_INTERNATIONAL_SURCHARGE_PERCENT	22	Surcharge for non-domestic destinations
COURIER_HEAVY_WEIGHT_THRESHOLD_KG	20	Heavy shipment threshold
COURIER_WEIGHT_PADDING_KG	0.500	Padding added to billable weight
COURIER_WEIGHT_INCREMENT_KG	0.500	Domestic weight multiplier increment
COURIER_DEFAULT_WEIGHT_UNIT	gram	Default unit for API requests
COURIER_DOMESTIC_USE_WEIGHT_MULTIPLIER	True	Per-increment pricing for domestic
COURIER_ZONE_RESOLVER	None	Custom (country_id, region_id) -> (connection, surcharge)

Plug into your own location models

# settings.py
COURIER_COUNTRY_MODEL = "myapp.Country"
COURIER_REGION_MODEL = "myapp.State"

def resolve_courier_zone(country_id, region_id):
    from courier.models import ZoneConnection
    # your lookup logic
    return connection, apply_surcharge

COURIER_ZONE_RESOLVER = resolve_courier_zone

Mark domestic countries with is_domestic=True on your model, or rely on COURIER_DOMESTIC_COUNTRY_NAME.

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Admin setup

1. Courier Country — add destinations; mark domestic with is_domestic
2. Courier Region — add states/provinces under domestic countries
3. Zone — create shipping zones (Zone A, Zone B, …)
4. Zone Connection — link zones to countries and/or regions
5. Weight Cost — set price per weight slab for each zone

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How pricing works

1. Resolve the destination zone from country/region via ZoneConnection
2. Normalize weight to grams and compute total billable weight
3. Look up the matching WeightCost slab for that zone
4. Domestic: multiply slab rate by weight increments (configurable)
5. International: apply configurable surcharge % on the base rate

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Development

git clone [e-mail]:nkscoder/courier.git
cd courier
pip install -e ".[admin]"
python manage.py migrate
python manage.py test courier

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Changelog

1.1.1

• Renamed PyPI package to nkscoder-courier (name courier was taken on PyPI)
• Fixed GitHub Actions publish workflow with PYPI_API_TOKEN

1.1.0

• Generic built-in CourierCountry / CourierRegion models (no core dependency)
• New calculate_courier_cost() service API
• Configurable settings via COURIER_* prefix
• Optional custom COURIER_ZONE_RESOLVER hook
• Improved admin with search and filters

1.0.0

• Initial PyPI release by Nitesh Kumar Singh (nkscoder)

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Author & Links

Author	Nitesh Kumar Singh
GitHub	github.com/nkscoder
Repository	github.com/nkscoder/courier
PyPI	pypi.org/project/nkscoder-courier

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License

MIT License — Copyright (c) 2020-2026 Nitesh Kumar Singh (nkscoder)