feat: invoice payment flow for paid relays

backend/spec/billing.md

@@ -26,12 +26,15 @@ Members:
 
 Manages the Stripe subscription and subscription items for a relay's tenant. Only paid (non-free) relays interact with Stripe. Free-only tenants have no subscription. Must be idempotent.
 
+Stripe uses **pay-in-advance** by default: when a subscription is first created, Stripe immediately generates an open invoice for the current period. The `invoice.created` webhook fires shortly after and `handle_invoice_created` attempts payment.
+
 - Fetch the relay and tenant associated with the `activity`
-- **If relay plan is `free`**: if the relay has a `stripe_subscription_item_id`, delete it via the Stripe API and call `command.delete_relay_subscription_item`. Then check cleanup (below). Return early.
+- **If relay plan is `free`**: if the relay has a `stripe_subscription_item_id`, delete it via the Stripe API and call `command.delete_relay_subscription_item`. Then run downgrade proration validation by previewing the upcoming invoice and logging proration lines/amounts. Then check cleanup (below). Return early.
 - **If relay is `inactive` or `delinquent`**: if the relay has a `stripe_subscription_item_id`, delete it via the Stripe API and call `command.delete_relay_subscription_item`. Then check cleanup (below). Return early.
 - **If relay is `active` and on a paid plan**:
   - **Ensure subscription exists**: If the tenant has no `stripe_subscription_id`, create a Stripe subscription for the customer with `collection_method: "charge_automatically"` and the relay's price as the first item. Save the subscription ID via `command.set_tenant_subscription` and the item ID via `command.set_relay_subscription_item`. Return early.
   - **Sync the subscription item**: If the tenant already has a subscription, create or update the relay's Stripe subscription item to the plan's `stripe_price_id` via the Stripe API, then call `command.set_relay_subscription_item`.
+  - **Downgrade validation**: when changing an existing subscription item, detect if the new plan amount is lower than the current one. If yes, preview the upcoming Stripe invoice and log proration line/amount details to validate expected credit/proration behavior.
 - **Clean up empty subscription**: After any item deletion, check if the tenant has any remaining active paid relays. If none and the tenant has a `stripe_subscription_id`, cancel the Stripe subscription immediately and call `command.clear_tenant_subscription`.
 
 ## `pub fn handle_webhook(&self, payload: &str, signature: &str) -> Result<()>`
@@ -44,6 +47,7 @@ Manages the Stripe subscription and subscription items for a relay's tenant. Onl
   - `invoice.overdue` -> `self.handle_invoice_overdue`
   - `customer.subscription.updated` -> `self.handle_subscription_updated`
   - `customer.subscription.deleted` -> `self.handle_subscription_deleted`
+  - `payment_method.attached` -> `self.handle_payment_method_attached`
 - Unknown event types are ignored (return Ok)
 
 ## `pub async fn stripe_list_invoices(&self, customer_id: &str) -> Result<Value>`
@@ -66,16 +70,37 @@ Manages the Stripe subscription and subscription items for a relay's tenant. Onl
 - Creates a Stripe Customer Portal session for the given customer
 - Returns the portal session URL
 
+## `pub async fn pay_outstanding_nwc_invoices(&self, tenant: &Tenant) -> Result<()>`
+
+Called when a tenant first sets their NWC URL (via `PUT /tenants/:pubkey`). Attempts to pay any currently open invoices for the tenant using their NWC wallet, so that invoices created before NWC was configured are not left unpaid.
+
+- If `tenant.nwc_url` is empty, return early.
+- List all Stripe invoices for `tenant.stripe_customer_id` via `stripe_list_invoices`.
+- For each invoice with `status == "open"` and `amount_due > 0`:
+  - Attempt NWC payment via `nwc_pay_invoice`.
+  - On success: call `stripe_pay_invoice_out_of_band` and `command.clear_tenant_nwc_error`.
+  - On failure: call `command.set_tenant_nwc_error` and log the error; continue to the next invoice.
+
+## `pub async fn pay_outstanding_card_invoices(&self, tenant: &Tenant) -> Result<()>`
+
+Attempts Stripe-side collection for open invoices when the tenant has a card on file.
+
+- If tenant has no card payment method, return early.
+- List all Stripe invoices for `tenant.stripe_customer_id`.
+- For each invoice with `status == "open"` and `amount_due > 0`:
+  - Call Stripe `POST /v1/invoices/:id/pay` to retry collection using the card on file.
+  - Log and continue on failures.
+
 ## `fn handle_invoice_created(&self, invoice: &Invoice)`
 
-Attempts to pay a new subscription invoice. Payment priority:
+Attempts to pay a new subscription invoice. Because Stripe defaults to pay-in-advance, this webhook fires immediately when a subscription is created (i.e. when a paid relay is added or a plan is upgraded). Payment priority:
 
 1. **NWC auto-pay**: If the tenant has a `nwc_url`:
    - Create a bolt11 Lightning invoice for the invoice amount using `self.nwc_url` (the receiving/system wallet)
    - Pay the bolt11 invoice using the tenant's `nwc_url` (the spending/tenant wallet)
    - If payment succeeds: call Stripe `POST /v1/invoices/:id/pay` with `paid_out_of_band: true`. Clear `nwc_error` via `command.clear_tenant_nwc_error`.
    - If payment fails: set `nwc_error` on tenant via `command.set_tenant_nwc_error`. Fall through to next option.
-2. **Card on file**: If the tenant has a payment method on the Stripe customer, do nothing — Stripe will charge automatically.
+2. **Card on file**: If the tenant has a payment method on the Stripe customer, do nothing here — Stripe will charge automatically for this invoice attempt.
 3. **Manual payment**: If neither NWC nor card is available, send a DM via `robot.send_dm` notifying the tenant that payment is due with a link to the application for manual Lightning payment.
 
 Skip invoices with `amount_due` of 0.
@@ -112,3 +137,8 @@ Skip invoices with `amount_due` of 0.
 
 - Look up tenant by `stripe_customer_id`
 - Clear `stripe_subscription_id` via `command.clear_tenant_subscription`
+
+## `fn handle_payment_method_attached(&self, stripe_customer_id: &str)`
+
+- Look up tenant by `stripe_customer_id`
+- Call `pay_outstanding_card_invoices` so invoices that were due before card setup are retried immediately

backend/src/api.rs

@@ -945,12 +945,29 @@ async fn update_tenant(
     state.api.require_admin_or_tenant(&auth, &pubkey)?;
     let mut tenant = state.api.get_tenant_or_404(&pubkey).await?;
 
+    let nwc_previously_empty = tenant.nwc_url.is_empty();
     if let Some(nwc_url) = payload.nwc_url {
         tenant.nwc_url = nwc_url;
     }
 
     match state.api.command.update_tenant(&tenant).await {
-        Ok(()) => Ok(ok(StatusCode::OK, tenant)),
+        Ok(()) => {
+            // When NWC is first connected, attempt to pay any outstanding open invoices.
+            if nwc_previously_empty && !tenant.nwc_url.is_empty() {
+                let billing = state.api.billing.clone();
+                let tenant_clone = tenant.clone();
+                tokio::spawn(async move {
+                    if let Err(e) = billing.pay_outstanding_nwc_invoices(&tenant_clone).await {
+                        tracing::error!(
+                            error = %e,
+                            pubkey = %tenant_clone.pubkey,
+                            "pay_outstanding_nwc_invoices failed after NWC setup"
+                        );
+                    }
+                });
+            }
+            Ok(ok(StatusCode::OK, tenant))
+        }
         Err(e) => Ok(err(
             StatusCode::INTERNAL_SERVER_ERROR,
             "internal",

backend/src/billing.rs

@@ -167,6 +167,8 @@ impl Billing {
                 self.command
                     .delete_relay_subscription_item(&relay.id)
                     .await?;
+                self.validate_downgrade_proration(&tenant, "free-plan-downgrade")
+                    .await;
             }
             self.cleanup_empty_subscription(&tenant.pubkey).await?;
             return Ok(());
@@ -206,8 +208,28 @@ impl Billing {
         // Sync the subscription item: create or update
         let subscription_id = tenant.stripe_subscription_id.as_ref().unwrap();
         let item_id = if let Some(ref existing_item_id) = relay.stripe_subscription_item_id {
-            self.stripe_update_subscription_item(existing_item_id, stripe_price_id)
-                .await?
+            let is_downgrade = self
+                .is_subscription_item_downgrade(existing_item_id, plan.amount)
+                .await
+                .unwrap_or_else(|error| {
+                    tracing::warn!(
+                        error = %error,
+                        relay_id = %relay.id,
+                        "failed to determine relay plan downgrade direction"
+                    );
+                    false
+                });
+
+            let updated_item_id = self
+                .stripe_update_subscription_item(existing_item_id, stripe_price_id)
+                .await?;
+
+            if is_downgrade {
+                self.validate_downgrade_proration(&tenant, "paid-plan-downgrade")
+                    .await;
+            }
+
+            updated_item_id
         } else {
             self.stripe_create_subscription_item(subscription_id, stripe_price_id)
                 .await?
@@ -275,6 +297,10 @@ impl Billing {
                 let customer = obj["customer"].as_str().unwrap_or_default();
                 self.handle_subscription_deleted(customer).await?;
             }
+            "payment_method.attached" => {
+                let customer = obj["customer"].as_str().unwrap_or_default();
+                self.handle_payment_method_attached(customer).await?;
+            }
             _ => {}
         }
 
@@ -492,6 +518,103 @@ impl Billing {
         Ok(())
     }
 
+    async fn handle_payment_method_attached(&self, stripe_customer_id: &str) -> Result<()> {
+        if stripe_customer_id.is_empty() {
+            return Ok(());
+        }
+
+        let Some(tenant) = self
+            .query
+            .get_tenant_by_stripe_customer_id(stripe_customer_id)
+            .await?
+        else {
+            return Ok(());
+        };
+
+        self.pay_outstanding_card_invoices(&tenant).await?;
+        Ok(())
+    }
+
+    async fn is_subscription_item_downgrade(
+        &self,
+        item_id: &str,
+        next_plan_amount: i64,
+    ) -> Result<bool> {
+        let Some(current_price_id) = self.stripe_get_subscription_item_price_id(item_id).await?
+        else {
+            return Ok(false);
+        };
+
+        let Some(current_plan_amount) = Self::plan_amount_from_price_id(&current_price_id) else {
+            return Ok(false);
+        };
+
+        Ok(next_plan_amount < current_plan_amount)
+    }
+
+    fn plan_amount_from_price_id(price_id: &str) -> Option<i64> {
+        Query::list_plans().into_iter().find_map(|plan| {
+            if plan.stripe_price_id.as_deref() == Some(price_id) {
+                Some(plan.amount)
+            } else {
+                None
+            }
+        })
+    }
+
+    async fn validate_downgrade_proration(&self, tenant: &crate::models::Tenant, context: &str) {
+        match self
+            .stripe_preview_upcoming_invoice(
+                &tenant.stripe_customer_id,
+                tenant.stripe_subscription_id.as_deref(),
+            )
+            .await
+        {
+            Ok(upcoming) => {
+                let lines = upcoming["lines"]["data"]
+                    .as_array()
+                    .cloned()
+                    .unwrap_or_default();
+                let proration_lines = lines
+                    .iter()
+                    .filter(|line| line["proration"].as_bool().unwrap_or(false))
+                    .count();
+                let amount_due = upcoming["amount_due"]
+                    .as_i64()
+                    .unwrap_or_else(|| upcoming["total"].as_i64().unwrap_or(0));
+                let currency = upcoming["currency"].as_str().unwrap_or("usd");
+                let preview_id = upcoming["id"].as_str().unwrap_or_default();
+
+                tracing::info!(
+                    tenant_pubkey = %tenant.pubkey,
+                    stripe_customer_id = %tenant.stripe_customer_id,
+                    context,
+                    preview_id,
+                    proration_lines,
+                    amount_due,
+                    currency,
+                    "validated Stripe proration preview for downgrade"
+                );
+
+                if proration_lines == 0 {
+                    tracing::warn!(
+                        tenant_pubkey = %tenant.pubkey,
+                        context,
+                        "downgrade proration preview has no proration lines; verify in Stripe dashboard"
+                    );
+                }
+            }
+            Err(error) => {
+                tracing::warn!(
+                    error = %error,
+                    tenant_pubkey = %tenant.pubkey,
+                    context,
+                    "failed to fetch downgrade proration preview"
+                );
+            }
+        }
+    }
+
     // --- Public API helpers ---
 
     pub async fn get_invoice_with_tenant(
@@ -599,6 +722,93 @@ impl Billing {
         Ok(invoice_response.invoice)
     }
 
+    pub async fn pay_outstanding_nwc_invoices(&self, tenant: &crate::models::Tenant) -> Result<()> {
+        if tenant.nwc_url.is_empty() {
+            return Ok(());
+        }
+
+        let invoices = self
+            .stripe_list_invoices(&tenant.stripe_customer_id)
+            .await?;
+        let invoices_arr = invoices.as_array().cloned().unwrap_or_default();
+
+        for invoice in &invoices_arr {
+            let status = invoice["status"].as_str().unwrap_or_default();
+            let amount_due = invoice["amount_due"].as_i64().unwrap_or(0);
+            let invoice_id = invoice["id"].as_str().unwrap_or_default();
+            let currency = invoice["currency"].as_str().unwrap_or("usd");
+
+            if status != "open" || amount_due == 0 || invoice_id.is_empty() {
+                continue;
+            }
+
+            match self
+                .nwc_pay_invoice(amount_due, currency, &tenant.nwc_url)
+                .await
+            {
+                Ok(()) => {
+                    if let Err(e) = self.stripe_pay_invoice_out_of_band(invoice_id).await {
+                        tracing::error!(
+                            error = %e,
+                            invoice_id,
+                            "failed to mark invoice paid out of band"
+                        );
+                    } else {
+                        let _ = self.command.clear_tenant_nwc_error(&tenant.pubkey).await;
+                    }
+                }
+                Err(e) => {
+                    let error_msg = format!("{e}");
+                    tracing::error!(
+                        error = %e,
+                        invoice_id,
+                        "nwc payment failed for outstanding invoice"
+                    );
+                    let _ = self
+                        .command
+                        .set_tenant_nwc_error(&tenant.pubkey, &error_msg)
+                        .await;
+                }
+            }
+        }
+
+        Ok(())
+    }
+
+    async fn pay_outstanding_card_invoices(&self, tenant: &crate::models::Tenant) -> Result<()> {
+        if !self
+            .stripe_has_payment_method(&tenant.stripe_customer_id)
+            .await?
+        {
+            return Ok(());
+        }
+
+        let invoices = self
+            .stripe_list_invoices(&tenant.stripe_customer_id)
+            .await?;
+        let invoices_arr = invoices.as_array().cloned().unwrap_or_default();
+
+        for invoice in &invoices_arr {
+            let status = invoice["status"].as_str().unwrap_or_default();
+            let amount_due = invoice["amount_due"].as_i64().unwrap_or(0);
+            let invoice_id = invoice["id"].as_str().unwrap_or_default();
+
+            if status != "open" || amount_due == 0 || invoice_id.is_empty() {
+                continue;
+            }
+
+            if let Err(error) = self.stripe_pay_invoice(invoice_id).await {
+                tracing::error!(
+                    error = %error,
+                    invoice_id,
+                    "failed to retry card payment for outstanding invoice"
+                );
+            }
+        }
+
+        Ok(())
+    }
+
     pub async fn stripe_create_portal_session(&self, customer_id: &str) -> Result<String> {
         let resp = self
             .http
@@ -715,6 +925,48 @@ impl Billing {
         Ok(())
     }
 
+    async fn stripe_pay_invoice(&self, invoice_id: &str) -> Result<()> {
+        self.http
+            .post(format!("{STRIPE_API}/invoices/{invoice_id}/pay"))
+            .bearer_auth(&self.stripe_secret_key)
+            .send()
+            .await?
+            .error_for_status()?;
+
+        Ok(())
+    }
+
+    async fn stripe_get_subscription_item_price_id(&self, item_id: &str) -> Result<Option<String>> {
+        let resp = self
+            .http
+            .get(format!("{STRIPE_API}/subscription_items/{item_id}"))
+            .bearer_auth(&self.stripe_secret_key)
+            .send()
+            .await?;
+
+        let body: serde_json::Value = resp.error_for_status()?.json().await?;
+        Ok(body["price"]["id"].as_str().map(ToString::to_string))
+    }
+
+    async fn stripe_preview_upcoming_invoice(
+        &self,
+        customer_id: &str,
+        subscription_id: Option<&str>,
+    ) -> Result<serde_json::Value> {
+        let mut req = self
+            .http
+            .get(format!("{STRIPE_API}/invoices/upcoming"))
+            .bearer_auth(&self.stripe_secret_key)
+            .query(&[("customer", customer_id)]);
+
+        if let Some(subscription_id) = subscription_id {
+            req = req.query(&[("subscription", subscription_id)]);
+        }
+
+        let body: serde_json::Value = req.send().await?.error_for_status()?.json().await?;
+        Ok(body)
+    }
+
     async fn stripe_pay_invoice_out_of_band(&self, invoice_id: &str) -> Result<()> {
         self.http
             .post(format!("{STRIPE_API}/invoices/{invoice_id}/pay"))

frontend/src/components/PaymentDialog.tsx

@@ -3,7 +3,6 @@ import QRCode from "qrcode"
 import Modal from "@/components/Modal"
 import PaymentSetup from "@/components/PaymentSetup"
 import { getInvoice, getInvoiceBolt11 } from "@/lib/api"
-import { tenantNeedsPaymentSetup } from "@/lib/hooks"
 
 type PayStatus = "idle" | "loading" | "success" | "error"
 type Bolt11Status = "idle" | "loading" | "ready" | "error"
@@ -26,8 +25,8 @@ export default function PaymentDialog(props: PaymentDialogProps) {
   const [bolt11Error, setBolt11Error] = createSignal("")
   const [payStatus, setPayStatus] = createSignal<PayStatus>("idle")
   const [payError, setPayError] = createSignal("")
-  const [showSetup, setShowSetup] = createSignal(false)
   const [showPaymentSetup, setShowPaymentSetup] = createSignal(false)
+  const [setupSaved, setSetupSaved] = createSignal(false)
 
   async function loadBolt11() {
     if (!props.invoice.id) return
@@ -63,7 +62,6 @@ export default function PaymentDialog(props: PaymentDialogProps) {
       const invoice = await getInvoice(props.invoice.id)
       if (invoice.status === "paid") {
         setPayStatus("success")
-        tenantNeedsPaymentSetup().then(needs => setShowSetup(needs)).catch(() => {})
       } else {
         setPayStatus("error")
         setPayError("Payment not yet confirmed. Please try again after sending.")
@@ -81,7 +79,6 @@ export default function PaymentDialog(props: PaymentDialogProps) {
     setBolt11Error("")
     setBolt11("")
     setQrDataUrl("")
-    setShowSetup(false)
     props.onClose()
   }
 
@@ -160,6 +157,15 @@ export default function PaymentDialog(props: PaymentDialogProps) {
                     </button>
                   </div>
                 </Show>
+                <div class="text-center pt-1">
+                  <button
+                    type="button"
+                    onClick={() => setShowPaymentSetup(true)}
+                    class="text-sm text-blue-600 hover:text-blue-700"
+                  >
+                    Set up payment method instead
+                  </button>
+                </div>
               </Show>
             </div>
           }
@@ -172,15 +178,13 @@ export default function PaymentDialog(props: PaymentDialogProps) {
             </div>
             <p class="text-sm font-medium text-gray-900">Payment confirmed!</p>
             <p class="text-xs text-gray-500">Thank you. Your account is up to date.</p>
-            <Show when={showSetup()}>
-              <button
-                type="button"
-                onClick={() => setShowPaymentSetup(true)}
-                class="mt-2 text-sm font-medium text-blue-600 hover:text-blue-700"
-              >
-                Set up automatic payments
-              </button>
-            </Show>
+            <button
+              type="button"
+              onClick={() => setShowPaymentSetup(true)}
+              class="mt-2 text-sm font-medium text-blue-600 hover:text-blue-700"
+            >
+              Set up automatic payments
+            </button>
           </div>
         </Show>
       </div>
@@ -228,7 +232,14 @@ export default function PaymentDialog(props: PaymentDialogProps) {
     </Modal>
     <PaymentSetup
       open={showPaymentSetup()}
-      onClose={() => setShowPaymentSetup(false)}
+      onClose={() => {
+        setShowPaymentSetup(false)
+        if (setupSaved()) {
+          setSetupSaved(false)
+          props.onClose()
+        }
+      }}
+      onSaved={() => setSetupSaved(true)}
     />
     </>
   )

frontend/src/components/PaymentSetup.tsx

@@ -9,6 +9,7 @@ type Tab = "nwc" | "card"
 type PaymentSetupProps = {
   open: boolean
   onClose: () => void
+  onSaved?: () => void
 }
 
 export default function PaymentSetup(props: PaymentSetupProps) {
@@ -27,6 +28,7 @@ export default function PaymentSetup(props: PaymentSetupProps) {
     try {
       await updateActiveTenant({ nwc_url: url })
       setSaved(true)
+      props.onSaved?.()
     } catch (e) {
       setError(e instanceof Error ? e.message : "Failed to save wallet connection")
     } finally {
@@ -64,7 +66,7 @@ export default function PaymentSetup(props: PaymentSetupProps) {
         <div class="flex items-start justify-between gap-3">
           <div>
             <h2 class="text-lg font-semibold text-gray-900">Set Up Payments</h2>
-            <p class="text-sm text-gray-500 mt-1">Choose how you'd like to pay for your relay.</p>
+            <p class="text-sm text-gray-500 mt-1">Choose how you'd like to pay once invoices are issued for your relay.</p>
           </div>
           <button
             type="button"
@@ -144,7 +146,7 @@ export default function PaymentSetup(props: PaymentSetupProps) {
                 <line x1="1" y1="10" x2="23" y2="10" />
               </svg>
             </div>
-            <p class="text-sm text-gray-600">Add a payment card via Stripe to enable automatic billing.</p>
+            <p class="text-sm text-gray-600">Add a payment card via Stripe to enable automatic billing. If an invoice is currently due, we will retry collection after card setup.</p>
             <button
               type="button"
               onClick={openPortal}

frontend/src/lib/hooks.ts

@@ -12,12 +12,14 @@ import {
   getTenant,
   listRelayActivity,
   listRelays,
+  listTenantInvoices,
   listTenantRelays,
   listTenants,
   updateRelay,
   updateTenant,
   type Activity,
   type CreateRelayInput,
+  type Invoice,
   type Relay,
   type Tenant,
   type UpdateRelayInput,
@@ -137,6 +139,14 @@ export async function tenantNeedsPaymentSetup(): Promise<boolean> {
   return !tenant.nwc_url && !tenant.stripe_subscription_id
 }
 
+export async function getLatestOpenInvoice(): Promise<Invoice | null> {
+  const invoices = await listTenantInvoices(account()!.pubkey)
+  const open = invoices
+    .filter(inv => inv.status === "open" && inv.amount_due > 0)
+    .sort((a, b) => b.period_start - a.period_start)
+  return open[0] ?? null
+}
+
 export async function getRelayMembers(url: string) {
   const management = new RelayManagement(new NostrRelay(url), account()!.signer)
 
@@ -147,4 +157,4 @@ export async function getRelayMembers(url: string) {
   }
 }
 
-export type { Activity, Relay, Tenant }
+export type { Activity, Invoice, Relay, Tenant }

frontend/src/lib/useRelayToggles.ts

@@ -1,7 +1,7 @@
 import { createSignal } from "solid-js"
-import { updateRelayById, deactivateRelayById, reactivateRelayById, tenantNeedsPaymentSetup, type Relay } from "@/lib/hooks"
+import { updateRelayById, deactivateRelayById, reactivateRelayById, getLatestOpenInvoice, type Relay } from "@/lib/hooks"
 import { setToastMessage } from "@/components/Toast"
-import type { PlanId } from "@/lib/api"
+import type { Invoice, PlanId } from "@/lib/api"
 
 function toBool(value: number | undefined, fallback: boolean): boolean {
   if (value === 0) return false
@@ -30,7 +30,7 @@ export default function useRelayToggles(
   { refetch, mutate }: RelayActions,
 ) {
   const [busy, setBusy] = createSignal(false)
-  const [needsPaymentSetup, setNeedsPaymentSetup] = createSignal(false)
+  const [pendingInvoice, setPendingInvoice] = createSignal<Invoice | undefined>()
 
   async function updateRelay(next: Relay, previous: Relay) {
     mutate(next)
@@ -101,8 +101,8 @@ export default function useRelayToggles(
     }
 
     if (plan !== "free") {
-      const needs = await tenantNeedsPaymentSetup()
-      if (needs) setNeedsPaymentSetup(true)
+      const invoice = await getLatestOpenInvoice()
+      if (invoice) setPendingInvoice(invoice)
     }
   }
 
@@ -116,5 +116,5 @@ export default function useRelayToggles(
     onToggleLivekitSupport: () => toggle("livekit_enabled", relay()?.plan !== "free"),
   }
 
-  return { busy, handleDeactivate, handleReactivate, handleUpdatePlan, needsPaymentSetup, clearNeedsPaymentSetup: () => setNeedsPaymentSetup(false), toggles }
+  return { busy, handleDeactivate, handleReactivate, handleUpdatePlan, pendingInvoice, clearPendingInvoice: () => setPendingInvoice(undefined), toggles }
 }

frontend/src/pages/relays/RelayDetail.tsx

@@ -1,14 +1,16 @@
 import { useParams } from "@solidjs/router"
-import { createMemo, createResource, Show } from "solid-js"
+import { createMemo, createResource, createSignal, Show } from "solid-js"
 import BackLink from "@/components/BackLink"
 import PageContainer from "@/components/PageContainer"
+import PaymentDialog from "@/components/PaymentDialog"
 import PaymentSetup from "@/components/PaymentSetup"
 import RelayDetailCard from "@/components/RelayDetailCard"
 import ResourceState from "@/components/ResourceState"
 import useMinLoading from "@/components/useMinLoading"
 import ActivityFeed from "@/components/ActivityFeed"
-import { getRelayMembers, useRelay, useRelayActivity } from "@/lib/hooks"
+import { getLatestOpenInvoice, getRelayMembers, useRelay, useRelayActivity, useTenant } from "@/lib/hooks"
 import useRelayToggles from "@/lib/useRelayToggles"
+import { plans } from "@/lib/state"
 
 export default function RelayDetail() {
   const params = useParams()
@@ -21,7 +23,32 @@ export default function RelayDetail() {
   const [members] = createResource(relayUrl, getRelayMembers)
   const loading = useMinLoading(() => relay.loading && !relay())
   const [activity] = useRelayActivity(relayId)
-  const { busy, handleDeactivate, handleReactivate, handleUpdatePlan, needsPaymentSetup, clearNeedsPaymentSetup, toggles } = useRelayToggles(relayId, relay, { refetch, mutate })
+  const { busy, handleDeactivate, handleReactivate, handleUpdatePlan, pendingInvoice, clearPendingInvoice, toggles } = useRelayToggles(relayId, relay, { refetch, mutate })
+
+  const [tenant, { refetch: refetchTenant }] = useTenant()
+  const [paymentSetupOpen, setPaymentSetupOpen] = createSignal(false)
+  const [invoiceDialogOpen, setInvoiceDialogOpen] = createSignal(false)
+  const [paymentBannerDismissed, setPaymentBannerDismissed] = createSignal(false)
+
+  const isPaidRelay = createMemo(() => {
+    const r = relay()
+    if (!r) return false
+    const plan = plans().find(p => p.id === r.plan)
+    return !!(plan && plan.amount > 0)
+  })
+
+  const [openInvoice, { refetch: refetchOpenInvoice }] = createResource(
+    isPaidRelay,
+    async (paid) => paid ? getLatestOpenInvoice() : null
+  )
+
+  const showPaymentNudge = createMemo(() => {
+    if (paymentBannerDismissed()) return false
+    if (!isPaidRelay()) return false
+    const t = tenant()
+    if (!t) return false
+    return !t.nwc_url
+  })
 
   return (
     <PageContainer>
@@ -30,6 +57,44 @@ export default function RelayDetail() {
       <Show when={!loading() && relay()}>
         {(r) => (
           <div class="space-y-6 mb-6">
+            <Show when={showPaymentNudge()}>
+              <div class="rounded-lg border border-amber-200 bg-amber-50 p-4 flex items-start justify-between gap-4">
+                <div class="min-w-0">
+                  <p class="text-sm font-medium text-amber-800">Payment setup recommended</p>
+                  <p class="text-sm text-amber-700 mt-1">
+                    This relay is on a paid plan. Invoices are due when your subscription starts. Set up NWC or Stripe for automatic payments, or pay open invoices via Lightning.
+                  </p>
+                </div>
+                <div class="flex items-center gap-3 shrink-0">
+                  <Show when={openInvoice()}>
+                    <button
+                      type="button"
+                      onClick={() => setInvoiceDialogOpen(true)}
+                      class="text-sm font-medium text-amber-800 underline hover:text-amber-900 whitespace-nowrap"
+                    >
+                      Pay invoice
+                    </button>
+                  </Show>
+                  <button
+                    type="button"
+                    onClick={() => setPaymentSetupOpen(true)}
+                    class="text-sm font-medium text-amber-800 underline hover:text-amber-900 whitespace-nowrap"
+                  >
+                    Set up payments
+                  </button>
+                  <button
+                    type="button"
+                    onClick={() => setPaymentBannerDismissed(true)}
+                    aria-label="Dismiss"
+                    class="text-amber-500 hover:text-amber-800 shrink-0"
+                  >
+                    <svg class="w-4 h-4" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round">
+                      <path d="M18 6L6 18M6 6l12 12" />
+                    </svg>
+                  </button>
+                </div>
+              </div>
+            </Show>
             <RelayDetailCard
               relay={r()}
               currentMembers={members.length}
@@ -45,9 +110,37 @@ export default function RelayDetail() {
           </div>
         )}
       </Show>
+      <Show when={pendingInvoice()}>
+        {(inv) => (
+          <PaymentDialog
+            invoice={inv()}
+            open={true}
+            onClose={() => {
+              clearPendingInvoice()
+              void refetchTenant()
+              void refetchOpenInvoice()
+            }}
+          />
+        )}
+      </Show>
+      <Show when={openInvoice()}>
+        {(inv) => (
+          <PaymentDialog
+            invoice={inv()!}
+            open={invoiceDialogOpen()}
+            onClose={() => {
+              setInvoiceDialogOpen(false)
+              void refetchOpenInvoice()
+            }}
+          />
+        )}
+      </Show>
       <PaymentSetup
-        open={needsPaymentSetup()}
-        onClose={clearNeedsPaymentSetup}
+        open={paymentSetupOpen()}
+        onClose={() => {
+          setPaymentSetupOpen(false)
+          void refetchTenant()
+        }}
       />
     </PageContainer>
   )

frontend/src/pages/relays/RelayNew.tsx

@@ -1,14 +1,15 @@
-import { createSignal } from "solid-js"
+import { createSignal, Show } from "solid-js"
 import { useNavigate } from "@solidjs/router"
 import BackLink from "@/components/BackLink"
 import PageContainer from "@/components/PageContainer"
-import PaymentSetup from "@/components/PaymentSetup"
+import PaymentDialog from "@/components/PaymentDialog"
 import RelayForm, { type RelayFormValues } from "@/components/RelayForm"
-import { createRelayForActiveTenant, tenantNeedsPaymentSetup } from "@/lib/hooks"
+import { createRelayForActiveTenant, getLatestOpenInvoice } from "@/lib/hooks"
+import type { Invoice } from "@/lib/api"
 
 export default function RelayNew() {
   const navigate = useNavigate()
-  const [showPaymentSetup, setShowPaymentSetup] = createSignal(false)
+  const [pendingInvoice, setPendingInvoice] = createSignal<Invoice | undefined>()
   let createdRelayId = ""
 
   async function handleSubmit(values: RelayFormValues) {
@@ -16,9 +17,9 @@ export default function RelayNew() {
     createdRelayId = relay.id
 
     if (values.plan !== "free") {
-      const needs = await tenantNeedsPaymentSetup()
-      if (needs) {
-        setShowPaymentSetup(true)
+      const invoice = await getLatestOpenInvoice()
+      if (invoice) {
+        setPendingInvoice(invoice)
         return
       }
     }
@@ -27,7 +28,7 @@ export default function RelayNew() {
   }
 
   function handleDialogClose() {
-    setShowPaymentSetup(false)
+    setPendingInvoice(undefined)
     navigate(`/relays/${createdRelayId}`)
   }
 
@@ -41,10 +42,15 @@ export default function RelayNew() {
         submitLabel="Create Relay"
         submittingLabel="Creating..."
       />
-      <PaymentSetup
-        open={showPaymentSetup()}
-        onClose={handleDialogClose}
-      />
+      <Show when={pendingInvoice()}>
+        {(inv) => (
+          <PaymentDialog
+            invoice={inv()}
+            open={true}
+            onClose={handleDialogClose}
+          />
+        )}
+      </Show>
     </PageContainer>
   )
 }