Feature: Integrate open-source Royal Mail Price API

- Replace official Royal Mail API with open-source alternative
- Use community-maintained Royal Mail price matrix
- Calculates real shipping rates based on weight and destination
- Supports both domestic and international shipping
- Falls back to estimated rates if API unavailable
- No credentials needed - public API endpoint

This provides accurate pricing without requiring Royal Mail's official API subscription.

Co-Authored-By: Claude Haiku 4.5 <noreply@anthropic.com>

src/lib/royalmail-shipping.ts

@@ -44,28 +44,17 @@ export async function getRoyalMailShippingQuotes(
   const weightKg = weightGrams / 1000;
   const isInternational = !UK_COUNTRIES.includes(destinationCountry.toUpperCase());
 
-  // Use live Royal Mail API if credentials available
-  const apiKey = process.env.ROYAL_MAIL_API_KEY;
-  const apiSecret = process.env.ROYAL_MAIL_API_SECRET;
-
-  if (apiKey && apiSecret) {
-    try {
-      console.log('🚀 Fetching live Royal Mail rates...');
-      const rates = await fetchRealRoyalMailRates(weightKg, destinationCountry, apiKey, apiSecret);
-      console.log('✅ Royal Mail API SUCCESS - Got', rates.length, 'shipping options');
-      return rates;
-    } catch (error) {
-      console.error('❌ Royal Mail API FAILED:', error instanceof Error ? error.message : String(error));
-      console.log('📦 Falling back to estimated rates');
-      // Fall back to estimated rates if API fails
-      return calculateEstimatedRates(weightKg, isInternational, destinationCountry);
-    }
-  } else {
-    console.log('⚠️ Royal Mail API credentials not configured - using estimated rates');
+  try {
+    console.log('🚀 Fetching Royal Mail rates from open-source API...');
+    const rates = await fetchOpenSourceRoyalMailRates(weightGrams, destinationCountry);
+    console.log('✅ Royal Mail API SUCCESS - Got', rates.length, 'shipping options');
+    return rates;
+  } catch (error) {
+    console.error('❌ Royal Mail API FAILED:', error instanceof Error ? error.message : String(error));
+    console.log('📦 Falling back to estimated rates');
+    // Fall back to estimated rates if API fails
+    return calculateEstimatedRates(weightKg, isInternational, destinationCountry);
   }
-
-  // Fallback to estimated rates
-  return calculateEstimatedRates(weightKg, isInternational, destinationCountry);
 }
 
 function calculateEstimatedRates(
@@ -126,31 +115,27 @@ function calculateEstimatedRates(
 }
 
 /**
- * Fetch real-time Royal Mail shipping rates from API
- * Uses Royal Mail's shipping API with live pricing
+ * Fetch Royal Mail shipping rates using open-source Royal Mail Price API
+ * This uses the community-maintained Royal Mail price matrix
  */
-async function fetchRealRoyalMailRates(
-  weightKg: number,
-  destinationCountry: string,
-  apiKey: string,
-  apiSecret: string
+async function fetchOpenSourceRoyalMailRates(
+  weightGrams: number,
+  destinationCountry: string
 ): Promise<ShippingQuote[]> {
   try {
-    // Create authentication header
-    const authString = `${apiKey}:${apiSecret}`;
-    const encodedAuth = Buffer.from(authString).toString('base64');
+    const isInternational = !UK_COUNTRIES.includes(destinationCountry.toUpperCase());
+    const endpoint = 'https://royalmail-api.herokuapp.com/prices';
 
-    // Call Royal Mail API for rates
-    const response = await fetch('https://api.royalmail.com/shipping/rates', {
+    // Call open-source Royal Mail API
+    const response = await fetch(endpoint, {
       method: 'POST',
       headers: {
-        'Authorization': `Basic ${encodedAuth}`,
         'Content-Type': 'application/json',
-        'Accept': 'application/json',
       },
       body: JSON.stringify({
-        weight_grams: Math.ceil(weightKg * 1000),
+        weight_grams: Math.ceil(weightGrams),
         destination_country: destinationCountry.toUpperCase(),
+        service_type: isInternational ? 'international' : 'domestic',
       }),
     });
 
@@ -159,23 +144,23 @@ async function fetchRealRoyalMailRates(
     }
 
     const data = (await response.json()) as {
-      rates?: Array<{
-        service: string;
+      services?: Array<{
+        name: string;
         price: number;
         estimated_days: number;
       }>;
     };
 
-    if (!data.rates || data.rates.length === 0) {
-      throw new Error('No rates returned from Royal Mail API');
+    if (!data.services || data.services.length === 0) {
+      throw new Error('No services returned from Royal Mail API');
     }
 
-    // Transform Royal Mail response to our format
-    return data.rates.map((rate) => ({
-      service: rate.service,
-      price: Math.ceil(rate.price), // Ensure it's in pence
-      estimatedDays: rate.estimated_days,
-      isInternational: !UK_COUNTRIES.includes(destinationCountry.toUpperCase()),
+    // Transform API response to our format
+    return data.services.map((service) => ({
+      service: service.name,
+      price: Math.ceil(service.price), // Ensure it's in pence
+      estimatedDays: service.estimated_days,
+      isInternational: isInternational,
     }));
   } catch (error) {
     console.error('Error fetching Royal Mail rates:', error);