Custom / REST API Integration

On a headless storefront or a platform without a first-party plugin? Build directly against the ShipRateAPI REST API — the same one every plugin uses.

REST API

Build your own integration on any platform

The ShipRateAPI REST API accepts a standard JSON payload from any platform or custom storefront. Normalise your checkout data to the standard format, pass your x-api-key and X-Platform: custom, and you get the same live rates the first-party plugins use.

One normalised endpoint

Every platform uses the same POST /api/v1/quotes endpoint. Map your checkout data to the standard JSON payload once and you’re done.

Simple API-key auth

Authenticate with an x-api-key header — no OAuth flow or token exchange. Each key is scoped to a single store.

Server-side & secure

Call the API from your backend so the key never reaches the browser, exactly as the first-party plugins do.

Same engine, same tags

You get the identical rating engine and routing-tag behaviour as the plugins — pass tags per line item to control carrier selection.

How it works

Four steps from API key to live rates at your checkout.

Generate an API key

Create a key in the admin portal under Settings → API Keys. It’s scoped to one store and shown in full only once.

Normalise your payload

Map your cart and destination to the standard JSON format — destination fields plus an items array with weight, price, and tags.

POST the rate request

Send it server-side with your x-api-key and the X-Platform: custom header so requests are attributed correctly in logs.

Render the rates

Read the response array and display only the methods where available is true, using amount as the customer-facing price.

Make your first request

Send a POST with a JSON body describing the destination and cart items. Authentication is a single x-api-key header — no token exchange.

A 200 OK returns an array of rate objects. Display only the methods where available is true, using amount as the customer-facing price. See the API Reference for every field.

curl -X POST https://api.shiprateapi.com/api/v1/quotes \
  -H "Content-Type: application/json" \
  -H "x-api-key: YOUR_API_KEY" \
  -H "X-Platform: custom" \
  -d '{
    "dest_country_id": "GB",
    "dest_postcode": "SW1A 1AA",
    "package_weight": 2.5,
    "package_value": 49.99,
    "items": [
      {
        "sku": "WIDGET-001",
        "name": "Blue Widget",
        "qty": 2,
        "price": 24.99,
        "weight": 1.25,
        "tags": ["fragile"]
      }
    ]
  }'

When to build a custom integration

If you’re on Shopify, Magento 2, BigCommerce, or commercetools, use the first-party integration. Reach for the REST API directly when:

Headless storefronts

A custom React, Vue, or mobile checkout calling your own backend for rates.

Unsupported platforms

WooCommerce, OpenCart, PrestaShop, or any cart without a first-party ShipRateAPI plugin.

ERP / OMS / middleware

Rating shipments inside an order management system, ERP, or internal tooling.

Start building

The Quick Start gets you from API key to a live rate in minutes. The API Reference and interactive Swagger UI cover every field and response.

Read the Quick Start API Reference Swagger UI