feat: Allow to pick currency when starting subscription

apps/api/src/controllers/Users.ts

@@ -190,6 +190,7 @@ export class Users {
   public async createCheckoutSession(req: Request, res: Response, _next: NextFunction) {
     const auth = res.locals.auth as AuthResponse;
     const {id} = UtilitySchemas.id.parse(req.params);
+    const {currency} = req.query;
 
     // Check if billing is enabled
     if (!STRIPE_ENABLED || !stripe) {
@@ -245,6 +246,17 @@ export class Users {
     const nextMonth = new Date(now.getFullYear(), now.getMonth() + 1, 1);
     const billingCycleAnchor = Math.floor(nextMonth.getTime() / 1000);
 
+    // Validate currency if provided
+    let checkoutCurrency: string | undefined;
+    if (currency && typeof currency === 'string') {
+      const validCurrencies = ['usd', 'eur', 'gbp'];
+      if (validCurrencies.includes(currency.toLowerCase())) {
+        checkoutCurrency = currency.toLowerCase();
+      } else {
+        return res.status(400).json({error: 'Invalid currency. Supported: USD, EUR, GBP'});
+      }
+    }
+
     // Create checkout session
     // Note: proration_behavior cannot be set when one-time prices are included
     // The billing_cycle_anchor alone ensures the subscription is anchored to the 1st of the month
@@ -253,6 +265,7 @@ export class Users {
       customer: project.customer ?? undefined, // Use existing customer if available
       client_reference_id: project.id, // Store project ID for webhook
       line_items: lineItems,
+      ...(checkoutCurrency && {currency: checkoutCurrency}),
       subscription_data: {
         billing_cycle_anchor: billingCycleAnchor,
       },

apps/web/src/pages/settings/index.tsx

@@ -27,6 +27,7 @@ import {
   Input,
   Select,
   SelectContent,
+  SelectItem,
   SelectItemWithDescription,
   SelectTrigger,
   SelectValue,
@@ -105,6 +106,8 @@ export default function Settings() {
   const [deleteConfirmText, setDeleteConfirmText] = useState('');
   const [resetConfirmText, setResetConfirmText] = useState('');
   const [isLoadingBilling, setIsLoadingBilling] = useState(false);
+  const [selectedCurrency, setSelectedCurrency] = useState<string>('auto');
+  const [showCurrencySelector, setShowCurrencySelector] = useState(false);
 
   // Fetch current user's membership for the active project
   const {data: membershipData} = useSWR<{
@@ -252,7 +255,7 @@ export default function Settings() {
     setShowRegenerateDialog(true);
   };
 
-  const handleStartSubscription = async () => {
+  const handleStartSubscription = async (currency: string = 'auto') => {
     if (!activeProject) return;
     if (!billingEnabled) {
       setErrorMessage('Billing is disabled on this instance.');
@@ -263,7 +266,13 @@ export default function Settings() {
       setIsLoadingBilling(true);
       setErrorMessage(null);
 
-      const response = await network.fetch<{url: string}>('POST', `/users/@me/projects/${activeProject.id}/checkout`);
+      // Build URL with optional currency parameter
+      const url =
+        currency === 'auto'
+          ? `/users/@me/projects/${activeProject.id}/checkout`
+          : `/users/@me/projects/${activeProject.id}/checkout?currency=${currency}`;
+
+      const response = await network.fetch<{url: string}>('POST', url);
 
       // Redirect to Stripe checkout
       if (response.url) {
@@ -666,10 +675,49 @@ export default function Settings() {
                             </p>
                           </div>
 
-                          <div className="flex justify-start">
-                            <Button onClick={handleStartSubscription} disabled={isLoadingBilling}>
-                              {isLoadingBilling ? 'Loading...' : 'Start Subscription'}
-                            </Button>
+                          <div className="flex flex-col gap-2">
+                            <div className="flex justify-start">
+                              <Button onClick={() => handleStartSubscription(selectedCurrency)} disabled={isLoadingBilling}>
+                                {isLoadingBilling ? 'Loading...' : 'Start Subscription'}
+                              </Button>
+                            </div>
+
+                            <div className="flex flex-col gap-2">
+                              <button
+                                type="button"
+                                onClick={() => setShowCurrencySelector(!showCurrencySelector)}
+                                className="text-xs text-neutral-500 hover:text-neutral-700 transition-colors w-fit"
+                              >
+                                {showCurrencySelector ? 'Hide currency options' : 'Select a different currency'}
+                              </button>
+
+                              <AnimatePresence>
+                                {showCurrencySelector && (
+                                  <motion.div
+                                    initial={{opacity: 0, height: 0}}
+                                    animate={{opacity: 1, height: 'auto'}}
+                                    exit={{opacity: 0, height: 0}}
+                                    transition={{duration: 0.2}}
+                                    className="overflow-hidden"
+                                  >
+                                    <div className="flex items-center gap-3 pt-1">
+                                      <label className="text-sm font-medium text-neutral-600">Currency:</label>
+                                      <Select value={selectedCurrency} onValueChange={setSelectedCurrency}>
+                                        <SelectTrigger className="w-[200px]">
+                                          <SelectValue />
+                                        </SelectTrigger>
+                                        <SelectContent>
+                                          <SelectItem value="auto">Auto-detect</SelectItem>
+                                          <SelectItem value="usd">USD ($) - US Dollar</SelectItem>
+                                          <SelectItem value="eur">EUR (€) - Euro</SelectItem>
+                                          <SelectItem value="gbp">GBP (£) - British Pound</SelectItem>
+                                        </SelectContent>
+                                      </Select>
+                                    </div>
+                                  </motion.div>
+                                )}
+                              </AnimatePresence>
+                            </div>
                           </div>
                         </div>
                       )}