Nova Post Global for OpenCart — international shipping rates at checkout

Nova Post Global for OpenCart puts Nova Poshta international shipping with a price right into checkout. A shopper from Germany, Poland or the US enters their address and immediately sees the cost of delivery abroad, instead of asking a manager “how much to Berlin?”. The rate comes from the official Nova Post Global API, calculated from the weight and size of that exact cart. Three builds: OpenCart 4.x, 3.x and 2.3.

What the buyer sees

The shipping step shows a “Nova Post Global — shipping abroad” method with a price in the store currency. It appears only for countries the NPG tariff covers and only for addresses outside Ukraine — Ukrainian buyers keep seeing regular Nova Poshta. If NPG doesn’t ship to the country (CALC004) or the weight is outside the tariff, the method simply doesn’t appear.

What the admin gets

One settings page: API login and password (the password is stored encrypted), production or test environment, service code, weight and size for products with empty fields, the per-piece limit, behaviour when the API fails, caching and an error log, geo zone, tax class and sort order. The “Test connection” button explains in plain words what’s wrong: a wrong password, a closed port 8243 or a country outside the tariff.

How it works, step by step

1. The buyer adds products to the cart and enters an address abroad.
2. The module packs the cart as one box: total actual weight, total volume, the longest item as the longest side. Store weight and length units are converted to kilograms and centimetres through the OpenCart core.
3. The request goes to the Nova Post Global API (IEW/publicCalculateCost) — Global Delivery Econom, the same product as in the public NPG calculator.
4. NPG returns the price in UAH; the module converts it to the store currency at the rate from “Localisation → Currencies”, and Pro adds a markup or makes shipping free above a total.
5. The price is cached, so the same cart to the same country doesn’t call the API on every checkout refresh.

Heavy orders (Pro). Econom carries one piece up to 68 kg, and to most countries only rates up to ~30 kg paid weight. Without Pro such an order gets no rate. Pro splits it into several identical pieces — by actual weight, and on a CALC005 answer by paid weight (actual or volumetric L×W×H/5000) — and shows the number of pieces in the method name.

Under the hood

• A regular OpenCart shipping extension, with no ocmod patches and no core file changes.
• An HTTP 424 answer with CALC004/CALC005/CALC006 is treated as a tariff answer and cached; network and authorisation errors aren’t cached, so the next request tries again.
• The API password is encrypted in the database: a DB dump won’t give it away in plain text.
• The same licence client as other CatCode modules: a 7-day trial.

How to install

1. Upload the build for your version via “Extensions → Installer”: cc_npglobal.ocmod.zip for OpenCart 4.x, cc_npglobal-oc3-1.0.0.ocmod.zip for 3.x, cc_npglobal-oc2-1.0.0.ocmod.zip for 2.3.
2. “Extensions → Extensions → Shipping”: install “Nova Post Global” and open its settings.
3. Enter the API login and password, enable the module, save and press “Test connection”.
4. Place a test order with an address abroad and check that the price appears in the shipping step.