feat: add lightning fees widget to dashboard

api/api.go

@@ -2119,3 +2119,38 @@ func (api *api) GetForwards() (*GetForwardsResponse, error) {
 		NumForwards:                 uint64(numForwards),
 	}, nil
 }
+
+func (api *api) GetTransactionStats() (*GetTransactionStatsResponse, error) {
+	var stats struct {
+		TotalVolumeMsat   uint64
+		TotalFeesPaidMsat uint64
+		NumPayments       uint64
+	}
+
+	// Aggregate settled outgoing payments. Self-payments are excluded because
+	// they never traverse the network and would dilute the fee rate towards zero.
+	//
+	// Scaling note: the WHERE is index-assisted via idx_transactions_state_type
+	// (no full table scan), but amount_msat/fee_msat are not in any index, so each
+	// matching row is fetched from the table to compute the SUM. This is fine for
+	// typical hubs (thousands of payments) but is O(outgoing settled rows) on every
+	// dashboard load. Before this needs to scale to millions of payments, add a
+	// covering index on transactions(type, state, self_payment, amount_msat, fee_msat)
+	// to make it an index-only scan, or maintain a cached running total.
+	err := api.db.Model(&db.Transaction{}).
+		Select("COALESCE(SUM(amount_msat), 0) AS total_volume_msat, COALESCE(SUM(fee_msat), 0) AS total_fees_paid_msat, COUNT(*) AS num_payments").
+		Where("type = ? AND state = ? AND self_payment = ?",
+			constants.TRANSACTION_TYPE_OUTGOING, constants.TRANSACTION_STATE_SETTLED, false).
+		Scan(&stats).Error
+	if err != nil {
+		return nil, err
+	}
+
+	return &GetTransactionStatsResponse{
+		TotalVolumeSat:    stats.TotalVolumeMsat / 1000,
+		TotalVolumeMsat:   stats.TotalVolumeMsat,
+		TotalFeesPaidSat:  stats.TotalFeesPaidMsat / 1000,
+		TotalFeesPaidMsat: stats.TotalFeesPaidMsat,
+		NumPayments:       stats.NumPayments,
+	}, nil
+}

api/models.go

@@ -82,6 +82,7 @@ type API interface {
 	ExecuteCustomNodeCommand(ctx context.Context, command string) (interface{}, error)
 	SendEvent(event string, properties interface{})
 	GetForwards() (*GetForwardsResponse, error)
+	GetTransactionStats() (*GetTransactionStatsResponse, error)
 }
 
 var ErrLNClientNotStarted = errors.New("LNClient not started")
@@ -711,6 +712,17 @@ type GetForwardsResponse struct {
 	NumForwards                 uint64 `json:"numForwards"`
 }
 
+// GetTransactionStatsResponse aggregates settled outgoing lightning payments
+// (excluding self-payments, which never traverse the network) so the frontend
+// can show a volume-weighted fee rate: TotalFeesPaidMsat / TotalVolumeMsat.
+type GetTransactionStatsResponse struct {
+	TotalVolumeSat    uint64 `json:"totalVolumeSat"`
+	TotalVolumeMsat   uint64 `json:"totalVolumeMsat"`
+	TotalFeesPaidSat  uint64 `json:"totalFeesPaidSat"`
+	TotalFeesPaidMsat uint64 `json:"totalFeesPaidMsat"`
+	NumPayments       uint64 `json:"numPayments"`
+}
+
 func ResolveToSat(satValue *uint64, msatValue *uint64, legacyValueSat *uint64, legacyValueMsat *uint64) (resolvedSatValue *uint64) {
 	if legacyValueSat != nil {
 		resolvedSatValue = legacyValueSat

api/transaction_stats_test.go

@@ -0,0 +1,86 @@
+package api
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+
+	"github.com/getAlby/hub/constants"
+	"github.com/getAlby/hub/db"
+	"github.com/getAlby/hub/tests"
+)
+
+func TestGetTransactionStats(t *testing.T) {
+	svc, err := tests.CreateTestService(t)
+	require.NoError(t, err)
+	defer svc.Remove()
+
+	// Two settled outgoing payments — these count towards the stats.
+	svc.DB.Create(&db.Transaction{
+		State:       constants.TRANSACTION_STATE_SETTLED,
+		Type:        constants.TRANSACTION_TYPE_OUTGOING,
+		PaymentHash: "hash1",
+		AmountMsat:  1_000_000,
+		FeeMsat:     3000,
+	})
+	svc.DB.Create(&db.Transaction{
+		State:       constants.TRANSACTION_STATE_SETTLED,
+		Type:        constants.TRANSACTION_TYPE_OUTGOING,
+		PaymentHash: "hash2",
+		AmountMsat:  500_000,
+		FeeMsat:     2000,
+	})
+	// Excluded: pending outgoing.
+	svc.DB.Create(&db.Transaction{
+		State:       constants.TRANSACTION_STATE_PENDING,
+		Type:        constants.TRANSACTION_TYPE_OUTGOING,
+		PaymentHash: "hash3",
+		AmountMsat:  999_000,
+		FeeMsat:     9000,
+	})
+	// Excluded: settled incoming.
+	svc.DB.Create(&db.Transaction{
+		State:       constants.TRANSACTION_STATE_SETTLED,
+		Type:        constants.TRANSACTION_TYPE_INCOMING,
+		PaymentHash: "hash4",
+		AmountMsat:  777_000,
+	})
+	// Excluded: self-payment (never traverses the network).
+	svc.DB.Create(&db.Transaction{
+		State:       constants.TRANSACTION_STATE_SETTLED,
+		Type:        constants.TRANSACTION_TYPE_OUTGOING,
+		PaymentHash: "hash5",
+		AmountMsat:  200_000,
+		FeeMsat:     0,
+		SelfPayment: true,
+	})
+
+	theAPI := &api{db: svc.DB}
+
+	stats, err := theAPI.GetTransactionStats()
+	require.NoError(t, err)
+	require.NotNil(t, stats)
+
+	assert.Equal(t, uint64(1_500_000), stats.TotalVolumeMsat)
+	assert.Equal(t, uint64(1500), stats.TotalVolumeSat)
+	assert.Equal(t, uint64(5000), stats.TotalFeesPaidMsat)
+	assert.Equal(t, uint64(5), stats.TotalFeesPaidSat)
+	assert.Equal(t, uint64(2), stats.NumPayments)
+}
+
+func TestGetTransactionStats_Empty(t *testing.T) {
+	svc, err := tests.CreateTestService(t)
+	require.NoError(t, err)
+	defer svc.Remove()
+
+	theAPI := &api{db: svc.DB}
+
+	stats, err := theAPI.GetTransactionStats()
+	require.NoError(t, err)
+	require.NotNil(t, stats)
+
+	assert.Equal(t, uint64(0), stats.TotalVolumeMsat)
+	assert.Equal(t, uint64(0), stats.TotalFeesPaidMsat)
+	assert.Equal(t, uint64(0), stats.NumPayments)
+}

frontend/src/components/home/widgets/FeeRateWidget.tsx

@@ -0,0 +1,47 @@
+import { FormattedBitcoinAmount } from "src/components/FormattedBitcoinAmount";
+import {
+  Card,
+  CardContent,
+  CardHeader,
+  CardTitle,
+} from "src/components/ui/card";
+import { useTransactionStats } from "src/hooks/useTransactionStats";
+
+function formatFeeRate(rate: number): string {
+  if (rate > 0 && rate < 0.01) {
+    return "<0.01%";
+  }
+  return `${rate.toFixed(2)}%`;
+}
+
+export function FeeRateWidget() {
+  const { data: stats } = useTransactionStats();
+
+  // Only show once there's payment volume to talk about — the volume-weighted
+  // rate is meaningless (and divides by zero) before the first payment.
+  if (!stats || !stats.totalVolumeMsat || !stats.numPayments) {
+    return null;
+  }
+
+  const feeRate = (stats.totalFeesPaidMsat / stats.totalVolumeMsat) * 100;
+
+  return (
+    <Card>
+      <CardHeader>
+        <CardTitle>Lightning fees</CardTitle>
+      </CardHeader>
+      <CardContent>
+        <p className="text-muted-foreground text-xs">Average fee rate</p>
+        <p className="text-3xl font-semibold">{formatFeeRate(feeRate)}</p>
+        <p className="text-muted-foreground text-sm mt-3">
+          You've sent{" "}
+          <FormattedBitcoinAmount amountMsat={stats.totalVolumeMsat} /> across{" "}
+          {stats.numPayments} payment{stats.numPayments === 1 ? "" : "s"} and
+          paid only{" "}
+          <FormattedBitcoinAmount amountMsat={stats.totalFeesPaidMsat} /> in
+          fees.
+        </p>
+      </CardContent>
+    </Card>
+  );
+}

frontend/src/hooks/useTransactionStats.ts

@@ -0,0 +1,11 @@
+import useSWR from "swr";
+
+import { GetTransactionStatsResponse } from "src/types";
+import { swrFetcher } from "src/utils/swr";
+
+export function useTransactionStats() {
+  return useSWR<GetTransactionStatsResponse>(
+    "/api/transactions/stats",
+    swrFetcher
+  );
+}

frontend/src/screens/Home.tsx

@@ -17,6 +17,7 @@ import { AlbyExtensionWidget } from "src/components/home/widgets/AlbyExtensionWi
 import { AlbyGoWidget } from "src/components/home/widgets/AlbyGoWidget";
 import { AppOfTheDayWidget } from "src/components/home/widgets/AppOfTheDayWidget";
 import { BlockHeightWidget } from "src/components/home/widgets/BlockHeightWidget";
+import { FeeRateWidget } from "src/components/home/widgets/FeeRateWidget";
 import { ForwardsWidget } from "src/components/home/widgets/ForwardsWidget";
 import { LatestUsedAppsWidget } from "src/components/home/widgets/LatestUsedAppsWidget";
 import { LightningMessageboardWidget } from "src/components/home/widgets/LightningMessageboardWidget";
@@ -45,6 +46,7 @@ function Home() {
       <div className="columns-1 lg:columns-2 gap-3 *:mb-3 *:break-inside-avoid">
         <OnboardingChecklist />
         <WhatsNewWidget />
+        <FeeRateWidget />
         <LatestUsedAppsWidget />
         <NewArrivalsWidget />
         <AppOfTheDayWidget />

frontend/src/types.ts

@@ -742,3 +742,11 @@ export type GetForwardsResponse = {
   totalFeeEarnedMsat: number;
   numForwards: number;
 };
+
+export type GetTransactionStatsResponse = {
+  totalVolumeSat: number;
+  totalVolumeMsat: number;
+  totalFeesPaidSat: number;
+  totalFeesPaidMsat: number;
+  numPayments: number;
+};

http/http_service.go

@@ -138,6 +138,7 @@ func (httpSvc *HttpService) RegisterSharedRoutes(e *echo.Echo) {
 	readOnlyApiGroup.GET("/wallet/address", httpSvc.onchainAddressHandler)
 	readOnlyApiGroup.GET("/wallet/capabilities", httpSvc.capabilitiesHandler)
 	readOnlyApiGroup.GET("/transactions", httpSvc.listTransactionsHandler)
+	readOnlyApiGroup.GET("/transactions/stats", httpSvc.transactionStatsHandler)
 	readOnlyApiGroup.GET("/transactions/:paymentHash", httpSvc.lookupTransactionHandler)
 	readOnlyApiGroup.GET("/balances", httpSvc.balancesHandler)
 	readOnlyApiGroup.GET("/mempool", httpSvc.mempoolApiHandler)
@@ -1606,3 +1607,14 @@ func (httpSvc *HttpService) forwardsHandler(c echo.Context) error {
 
 	return c.JSON(http.StatusOK, forwards)
 }
+
+func (httpSvc *HttpService) transactionStatsHandler(c echo.Context) error {
+	stats, err := httpSvc.api.GetTransactionStats()
+	if err != nil {
+		return c.JSON(http.StatusInternalServerError, ErrorResponse{
+			Message: fmt.Sprintf("Failed to get transaction stats: %s", err.Error()),
+		})
+	}
+
+	return c.JSON(http.StatusOK, stats)
+}