diff --git a/app/profile/page.tsx b/app/profile/page.tsx
index 22f82ce..ae60c6e 100644
--- a/app/profile/page.tsx
+++ b/app/profile/page.tsx
@@ -1,12 +1,21 @@
 "use client";
 
-import { useMemo, useState } from "react";
+import { useEffect, useMemo, useState } from "react";
 import Link from "next/link";
 import { useWallet } from "@/contexts/WalletContext";
 import { useSelectedNetwork } from "@/hooks/useSelectedNetwork";
 import { CopyHashButton } from "@/components/ui/CopyHashButton";
 import { ProfileSkeleton } from "@/components/ProfileSkeleton";
 import { isValidStellarPublicKey } from "@/lib/stellar-address";
+import { CashflowChart } from "@/components/profile/CashflowChart";
+import {
+  computeCashflow,
+  CASHFLOW_WINDOW_DAYS,
+  type CashflowStream,
+} from "@/lib/profile-analytics";
+import { streamsBySender, streamsByRecipient } from "@/lib/factory";
+import { getStreamAddress, getStreamInfo } from "@/lib/stream";
+import { fromStroops } from "@/lib/format";
 
 type ConnectionState =
   | { status: "loading" }
@@ -24,6 +33,108 @@ function useConnectionState(): ConnectionState {
   return { status: "disconnected" };
 }
 
+/**
+ * Aggregated incoming vs outgoing streaming volume over the trailing 30 days
+ * (#690). Resolves the user's stream IDs in both directions, estimates
+ * per-day volume as rate × overlap, and renders totals + a stacked bar chart.
+ */
+function CashflowSection({ publicKey }: { publicKey: string }) {
+  const [streams, setStreams] = useState<CashflowStream[]>([]);
+  const [loading, setLoading] = useState(true);
+
+  useEffect(() => {
+    let active = true;
+    setLoading(true);
+    (async () => {
+      try {
+        const [senderIds, recipientIds] = await Promise.all([
+          streamsBySender(publicKey, publicKey, 0, 50).catch(() => [] as bigint[]),
+          streamsByRecipient(publicKey, publicKey, 0, 50).catch(() => [] as bigint[]),
+        ]);
+        const jobs: { id: bigint; direction: "incoming" | "outgoing" }[] = [
+          ...senderIds.map((id) => ({ id, direction: "outgoing" as const })),
+          ...recipientIds.map((id) => ({ id, direction: "incoming" as const })),
+        ];
+        const settled = await Promise.allSettled(
+          jobs.map(async (job) => {
+            const addr = await getStreamAddress(publicKey, job.id);
+            if (!addr) return null;
+            const info = await getStreamInfo(publicKey, addr);
+            return { info, direction: job.direction } as CashflowStream;
+          }),
+        );
+        if (!active) return;
+        setStreams(
+          settled.flatMap((r) =>
+            r.status === "fulfilled" && r.value ? [r.value] : [],
+          ),
+        );
+      } catch {
+        if (active) setStreams([]);
+      } finally {
+        if (active) setLoading(false);
+      }
+    })();
+    return () => {
+      active = false;
+    };
+  }, [publicKey]);
+
+  const summary = useMemo(
+    () =>
+      computeCashflow(
+        streams,
+        Math.floor(Date.now() / 1000),
+        CASHFLOW_WINDOW_DAYS,
+      ),
+    [streams],
+  );
+
+  return (
+    <div className="card mb-6">
+      <h2 className="text-sm font-semibold text-gray-400 dark:text-gray-500 uppercase tracking-wider mb-1">
+        Cash Flow — past {CASHFLOW_WINDOW_DAYS} days
+      </h2>
+      <p className="text-xs text-gray-400 dark:text-gray-500 mb-4">
+        Estimated streaming income vs expenditure from active stream rates.
+      </p>
+      {loading ? (
+        <div className="py-10 text-center text-sm text-gray-400" aria-busy="true">
+          Loading cash flow…
+        </div>
+      ) : (
+        <>
+          <div className="grid grid-cols-3 gap-3 mb-5">
+            <div>
+              <p className="text-[11px] text-gray-400 dark:text-gray-500">Income</p>
+              <p className="text-lg font-black font-mono" data-testid="cashflow-incoming">
+                {fromStroops(summary.totalIncoming)}
+              </p>
+            </div>
+            <div>
+              <p className="text-[11px] text-gray-400 dark:text-gray-500">Spent</p>
+              <p className="text-lg font-black font-mono" data-testid="cashflow-outgoing">
+                {fromStroops(summary.totalOutgoing)}
+              </p>
+            </div>
+            <div>
+              <p className="text-[11px] text-gray-400 dark:text-gray-500">Net</p>
+              <p
+                className={`text-lg font-black font-mono ${summary.net >= 0n ? "text-green-600 dark:text-green-400" : "text-red-600 dark:text-red-400"}`}
+                data-testid="cashflow-net"
+              >
+                {summary.net >= 0n ? "+" : "−"}
+                {fromStroops(summary.net >= 0n ? summary.net : -summary.net)}
+              </p>
+            </div>
+          </div>
+          <CashflowChart daily={summary.daily} />
+        </>
+      )}
+    </div>
+  );
+}
+
 export default function ProfilePage() {
   const connection = useConnectionState();
   const { disconnect } = useWallet();
@@ -125,6 +236,8 @@ export default function ProfilePage() {
               </div>
             </div>
 
+            <CashflowSection publicKey={publicKey} />
+
             <div className="card">
               <h2 className="text-sm font-semibold text-gray-400 dark:text-gray-500 uppercase tracking-wider mb-4">
                 Quick Links
diff --git a/app/settings/page.tsx b/app/settings/page.tsx
index ae58346..827259c 100644
--- a/app/settings/page.tsx
+++ b/app/settings/page.tsx
@@ -5,6 +5,15 @@ import { useTheme } from "next-themes";
 import { NetworkName, NETWORKS } from "@/lib/network-config";
 import { saveSelectedNetwork } from "@/lib/network-storage";
 import { useOnboarding } from "@/hooks/useOnboarding";
+import {
+  clearCustomRpcUrl,
+  getCustomRpcUrl,
+  isValidRpcUrl,
+  pingRpcEndpoint,
+  saveCustomRpcUrl,
+  type RpcPingResult,
+} from "@/lib/custom-rpc";
+import { resetServer } from "@/lib/soroban";
 import {
   type TimeFormat,
   type RefreshIntervalSeconds,
@@ -73,6 +82,18 @@ export default function SettingsPage() {
   const [saved, setSaved] = useState(false);
   const didMount = useRef(false);
 
+  // #691 — custom RPC endpoint override (local sandbox / private node).
+  const [customRpc, setCustomRpc] = useState("");
+  const [savedCustomRpc, setSavedCustomRpc] = useState<string | null>(null);
+  const [ping, setPing] = useState<RpcPingResult | null>(null);
+  const [pinging, setPinging] = useState(false);
+  const [rpcMessage, setRpcMessage] = useState<string | null>(null);
+
+  useEffect(() => {
+    setSavedCustomRpc(getCustomRpcUrl());
+    setCustomRpc(getCustomRpcUrl() ?? "");
+  }, []);
+
   useEffect(() => {
     if (!didMount.current) {
       didMount.current = true;
@@ -113,6 +134,59 @@ export default function SettingsPage() {
     setTimeout(() => setSaved(false), 2000);
   }, [setTheme]);
 
+  const handleTestPing = useCallback(async () => {
+    setRpcMessage(null);
+    setPing(null);
+    if (!isValidRpcUrl(customRpc)) {
+      setPing({ ok: false, latencyMs: null, error: "Enter a valid http(s) RPC URL." });
+      return;
+    }
+    setPinging(true);
+    try {
+      const result = await pingRpcEndpoint(customRpc.trim());
+      setPing(result);
+    } finally {
+      setPinging(false);
+    }
+  }, [customRpc]);
+
+  const handleSaveCustomRpc = useCallback(async () => {
+    setRpcMessage(null);
+    const url = customRpc.trim();
+    if (!isValidRpcUrl(url)) {
+      setPing({ ok: false, latencyMs: null, error: "Enter a valid http(s) RPC URL." });
+      return;
+    }
+    // Validate latency before saving — ping first, save only on success.
+    setPinging(true);
+    try {
+      const result = await pingRpcEndpoint(url);
+      setPing(result);
+      if (!result.ok) return;
+      saveCustomRpcUrl(url);
+      resetServer();
+      setSavedCustomRpc(url);
+      setRpcMessage(`Custom RPC saved (${result.latencyMs} ms).`);
+    } catch (e) {
+      setPing({
+        ok: false,
+        latencyMs: null,
+        error: e instanceof Error ? e.message : "Could not save the RPC endpoint.",
+      });
+    } finally {
+      setPinging(false);
+    }
+  }, [customRpc]);
+
+  const handleClearCustomRpc = useCallback(() => {
+    clearCustomRpcUrl();
+    resetServer();
+    setSavedCustomRpc(null);
+    setCustomRpc("");
+    setPing(null);
+    setRpcMessage("Custom RPC cleared — using the preset network endpoint.");
+  }, []);
+
   return (
     <div className="max-w-2xl mx-auto px-4 py-10 space-y-8">
       <div className="flex items-center justify-between">
@@ -173,6 +247,78 @@ export default function SettingsPage() {
             ))}
           </select>
         </div>
+
+        {/* Custom RPC endpoint override (#691) */}
+        <div className="mt-5 border-t border-gray-100 dark:border-gray-800 pt-4">
+          <span className="text-sm font-medium">Custom RPC endpoint</span>
+          <p className="text-xs text-gray-400 dark:text-gray-500 mt-0.5 mb-3">
+            Override the preset endpoint with a local sandbox or private node
+            (e.g. QuickNode, Triton). Ping it first — saving requires a
+            successful response.
+          </p>
+          <div className="flex flex-col gap-2">
+            <input
+              type="url"
+              value={customRpc}
+              onChange={(e) => {
+                setCustomRpc(e.target.value);
+                setPing(null);
+                setRpcMessage(null);
+              }}
+              placeholder="https://my-private-rpc.example.com"
+              aria-label="Custom RPC endpoint"
+              className="w-full bg-gray-100 dark:bg-gray-800 border border-gray-200 dark:border-gray-700 rounded px-3 py-1.5 text-sm font-mono"
+            />
+            <div className="flex flex-wrap items-center gap-2">
+              <button
+                type="button"
+                onClick={handleTestPing}
+                disabled={pinging || !customRpc.trim()}
+                className="px-4 py-1.5 rounded text-sm font-medium border border-gray-300 dark:border-gray-700 text-black dark:text-white hover:bg-gray-50 dark:hover:bg-gray-900 transition-colors disabled:opacity-50 disabled:cursor-not-allowed"
+              >
+                {pinging ? "Pinging…" : "Test Ping"}
+              </button>
+              <button
+                type="button"
+                onClick={handleSaveCustomRpc}
+                disabled={pinging || !isValidRpcUrl(customRpc)}
+                className="px-4 py-1.5 rounded text-sm font-medium bg-black text-white dark:bg-white dark:text-black disabled:opacity-50 disabled:cursor-not-allowed"
+              >
+                Save endpoint
+              </button>
+              {savedCustomRpc && (
+                <button
+                  type="button"
+                  onClick={handleClearCustomRpc}
+                  className="px-4 py-1.5 rounded text-sm font-medium text-gray-500 hover:text-black dark:hover:text-white underline"
+                >
+                  Clear override
+                </button>
+              )}
+            </div>
+            {ping && (
+              <p
+                role="status"
+                data-testid="rpc-ping-result"
+                className={`text-xs font-mono ${ping.ok ? "text-green-600 dark:text-green-400" : "text-red-600 dark:text-red-400"}`}
+              >
+                {ping.ok
+                  ? `Reachable — ${ping.latencyMs} ms.`
+                  : `Unreachable${ping.latencyMs !== null ? ` (${ping.latencyMs} ms)` : ""}: ${ping.error ?? "no response"}`}
+              </p>
+            )}
+            {rpcMessage && (
+              <p role="status" className="text-xs text-gray-500 dark:text-gray-400">
+                {rpcMessage}
+              </p>
+            )}
+            {savedCustomRpc && (
+              <p className="text-xs text-gray-400 dark:text-gray-500 break-all">
+                Active override: <span className="font-mono">{savedCustomRpc}</span>
+              </p>
+            )}
+          </div>
+        </div>
       </section>
 
       {/* Currency & Slippage */}
diff --git a/app/stream/[id]/page.tsx b/app/stream/[id]/page.tsx
index d344101..9446ba1 100644
--- a/app/stream/[id]/page.tsx
+++ b/app/stream/[id]/page.tsx
@@ -3,11 +3,12 @@
 import { useCallback, useEffect, useRef, useState } from "react";
 import { useParams } from "next/navigation";
 import Link from "next/link";
-import { ArrowLeft, FileText } from "lucide-react";
+import { ArrowLeft, FileText, Share2 } from "lucide-react";
 
 import { Badge } from "@/components/ui/Badge";
 import { Card } from "@/components/ui/Card";
 import { CopyAddress } from "@/components/ui/CopyAddress";
+import { QrCodeModal } from "@/components/ui/QrCodeModal";
 import { RateTicker } from "@/components/stream/RateTicker";
 import { StreamTimeline } from "@/components/stream/StreamTimeline";
 import { StreamFlowChart } from "@/components/stream/StreamFlowChart";
@@ -68,6 +69,8 @@ export default function StreamPage() {
   const [loading, setLoading] = useState(true);
   const [error, setError] = useState<string | null>(null);
   const [status, setStatus] = useState<StreamStatus>("active");
+  // #688 — shareable claim-link QR modal state.
+  const [shareOpen, setShareOpen] = useState(false);
 
   // Use stream note hook — only available after streamAddress is resolved
   const noteHook = useStreamNote(streamAddress || "");
@@ -255,6 +258,14 @@ export default function StreamPage() {
     tokenByAddress(info.token, "testnet")?.symbol ??
     truncateAddress(info.token);
 
+  // #688 — direct stream claim URL for QR sharing. Built from the current
+  // origin on the client so a scanned code opens this exact stream page
+  // (claim/monitor) on the recipient's device.
+  const claimUrl =
+    typeof window !== "undefined"
+      ? `${window.location.origin}/stream/${id}`
+      : `/stream/${id}`;
+
   return (
     <div
       className="max-w-2xl mx-auto px-4 py-10 print-receipt"
@@ -284,6 +295,16 @@ export default function StreamPage() {
         </div>
         <div className="flex items-center gap-2">
           <Badge status={status} />
+          {/* Share stream claim link via QR code (#688) */}
+          <button
+            type="button"
+            onClick={() => setShareOpen(true)}
+            className="inline-flex items-center gap-1.5 px-3 py-1.5 rounded text-xs font-medium border border-gray-300 dark:border-gray-700 text-black dark:text-white hover:bg-gray-50 dark:hover:bg-gray-900 transition-colors print:hidden"
+            aria-label="Share stream"
+          >
+            <Share2 className="w-3.5 h-3.5" aria-hidden="true" />
+            Share
+          </button>
           {/* Add stream end date to an external calendar (#566) */}
           {info.endTime > 0 && (
             <AddToCalendarButton
@@ -524,6 +545,15 @@ export default function StreamPage() {
           tokens at any time.
         </p>
       )}
+
+      {/* Share stream claim-link QR modal (#688) */}
+      {shareOpen && (
+        <QrCodeModal
+          value={claimUrl}
+          title={`Share Stream #${id}`}
+          onClose={() => setShareOpen(false)}
+        />
+      )}
     </div>
   );
 }
diff --git a/app/streams/compare/page.tsx b/app/streams/compare/page.tsx
index 65dbe93..f44af68 100644
--- a/app/streams/compare/page.tsx
+++ b/app/streams/compare/page.tsx
@@ -176,16 +176,28 @@ function CompareView() {
       </div>
     );
   } else {
+    // #689 — responsive multi-column grid: 2 columns fit comfortably, 3–4
+    // columns scroll horizontally on small screens and sit side-by-side on
+    // lg+ (max-w-6xl). Each stream gets an equal min-width column so 3 or 4
+    // schedules remain comparable without squashing.
+    const columnCount = columns.length;
     body = (
-      <div className="card p-0 overflow-x-auto">
-        <table className="w-full text-sm border-collapse">
+      <div
+        className="card p-0 overflow-x-auto"
+        data-testid="compare-grid"
+        data-columns={columnCount}
+      >
+        <table
+          className="w-full text-sm border-collapse"
+          style={{ minWidth: columnCount >= 4 ? 860 : columnCount >= 3 ? 720 : 520 }}
+        >
           <thead>
             <tr className="border-b border-gray-200 dark:border-gray-800">
-              <th scope="col" className="text-left p-3 text-xs font-medium text-gray-400 dark:text-gray-500 w-32">
+              <th scope="col" className="text-left p-3 text-xs font-medium text-gray-400 dark:text-gray-500 w-32 min-w-[120px] sticky left-0 bg-white dark:bg-gray-950 z-10">
                 <span className="sr-only">Metric</span>
               </th>
               {columns.map((col) => (
-                <th key={col.id} scope="col" className="text-left p-3 font-black">
+                <th key={col.id} scope="col" className="text-left p-3 font-black min-w-[150px] sm:min-w-[170px]">
                   <Link href={`/stream/${col.id}`} className="hover:underline">Stream #{col.id}</Link>
                 </th>
               ))}
@@ -194,11 +206,11 @@ function CompareView() {
           <tbody>
             {ROWS.map((row) => (
               <tr key={row.label} className="border-b last:border-b-0 border-gray-100 dark:border-gray-800/60">
-                <th scope="row" className="text-left p-3 text-xs font-medium text-gray-400 dark:text-gray-500 whitespace-nowrap align-top">
+                <th scope="row" className="text-left p-3 text-xs font-medium text-gray-400 dark:text-gray-500 whitespace-nowrap align-top sticky left-0 bg-white dark:bg-gray-950 z-10">
                   {row.label}
                 </th>
                 {columns.map((col) => (
-                  <td key={col.id} className="p-3 align-top">
+                  <td key={col.id} className="p-3 align-top min-w-[150px] sm:min-w-[170px]">
                     {col.kind === 'error' ? (
                       row === ROWS[0] ? <span role="alert" className="text-xs text-gray-500">{col.message}</span> : <span className="text-gray-300 dark:text-gray-700">—</span>
                     ) : (
@@ -218,11 +230,17 @@ function CompareView() {
   }
 
   return (
-    <div className="max-w-5xl mx-auto px-4 py-10">
+    <div className="max-w-6xl mx-auto px-4 py-10">
       <Link href="/streams" className="inline-flex items-center gap-1.5 text-xs text-gray-400 hover:text-black dark:hover:text-white mb-6">
         <ArrowLeft className="w-3.5 h-3.5" /> All streams
       </Link>
-      <h1 className="text-2xl font-black tracking-tight mb-8">Compare streams</h1>
+      <h1 className="text-2xl font-black tracking-tight mb-2">Compare streams</h1>
+      {columns.length >= 2 && (
+        <p className="text-xs text-gray-400 dark:text-gray-500 mb-6">
+          Comparing {columns.length} of up to {MAX_COMPARE} streams side-by-side
+        </p>
+      )}
+      {columns.length < 2 && <div className="mb-6" />}
       {overLimit && connected && publicKey && (
         <div role="status" className="card mb-4 text-sm text-gray-500 dark:text-gray-400">
           You can compare up to {MAX_COMPARE} streams at a time. Showing the first {MAX_COMPARE} of the{' '}
diff --git a/components/profile/CashflowChart.tsx b/components/profile/CashflowChart.tsx
new file mode 100644
index 0000000..7b14072
--- /dev/null
+++ b/components/profile/CashflowChart.tsx
@@ -0,0 +1,102 @@
+"use client";
+
+import { useMemo } from "react";
+import { fromStroops } from "@/lib/format";
+import type { DailyFlow } from "@/lib/profile-analytics";
+
+interface CashflowChartProps {
+  daily: DailyFlow[];
+}
+
+/**
+ * Stacked bar chart of daily streaming income (bottom, dark) vs expenditure
+ * (top, gray) over the trailing 30-day window (#690). Pure CSS/divs — no
+ * chart dependency. Bars scale to the busiest day in the window.
+ */
+export function CashflowChart({ daily }: CashflowChartProps) {
+  const max = useMemo(() => {
+    let m = 0n;
+    for (const d of daily) {
+      const total = d.incoming + d.outgoing;
+      if (total > m) m = total;
+    }
+    return m > 0n ? m : 1n;
+  }, [daily]);
+
+  const hasData = daily.some((d) => d.incoming > 0n || d.outgoing > 0n);
+  if (!hasData) {
+    return (
+      <div
+        role="status"
+        data-testid="cashflow-empty"
+        className="flex flex-col items-center justify-center text-center py-10"
+      >
+        <p className="text-sm font-semibold">No streaming activity yet</p>
+        <p className="text-xs text-gray-400 dark:text-gray-500 mt-1">
+          Income vs expenditure will appear here once you send or receive streams.
+        </p>
+      </div>
+    );
+  }
+
+  return (
+    <div data-testid="cashflow-chart">
+      <div
+        className="flex items-end gap-1 h-36"
+        role="img"
+        aria-label="Daily streaming income versus expenditure over the past 30 days"
+      >
+        {daily.map((d) => {
+          const total = d.incoming + d.outgoing;
+          const totalPct = total > 0n ? Number((total * 1000n) / max) / 10 : 0;
+          const incomingPct =
+            total > 0n ? (Number((d.incoming * 1000n) / total) / 10) * (totalPct / 100) * 100 : 0;
+          const outgoingPct = totalPct - incomingPct;
+          return (
+            <div
+              key={d.dayStart}
+              className="flex-1 flex flex-col justify-end h-full min-w-0"
+              title={`${d.label}: +${fromStroops(d.incoming)} in / -${fromStroops(d.outgoing)} out`}
+            >
+              <div
+                data-testid={`cashflow-bar-${d.dayStart}`}
+                className="w-full flex flex-col-reverse rounded-sm overflow-hidden"
+                style={{ height: `${Math.max(totalPct, total > 0n ? 4 : 0)}%` }}
+              >
+                {outgoingPct > 0 && (
+                  <div
+                    className="w-full bg-gray-300 dark:bg-gray-600"
+                    style={{ height: `${(outgoingPct / totalPct) * 100}%` }}
+                  />
+                )}
+                {incomingPct > 0 && (
+                  <div
+                    className="w-full bg-black dark:bg-white"
+                    style={{
+                      height: `${(incomingPct / totalPct) * 100}%`,
+                      minHeight: d.incoming > 0n ? 2 : 0,
+                    }}
+                  />
+                )}
+              </div>
+            </div>
+          );
+        })}
+      </div>
+      <div className="flex justify-between mt-2 text-[10px] font-mono text-gray-400 dark:text-gray-500">
+        <span>{daily[0]?.label}</span>
+        <span>{daily[daily.length - 1]?.label}</span>
+      </div>
+      <div className="flex items-center gap-4 mt-3 text-xs text-gray-500 dark:text-gray-400">
+        <span className="inline-flex items-center gap-1.5">
+          <span className="inline-block w-2.5 h-2.5 rounded-sm bg-black dark:bg-white" aria-hidden="true" />
+          Income
+        </span>
+        <span className="inline-flex items-center gap-1.5">
+          <span className="inline-block w-2.5 h-2.5 rounded-sm bg-gray-300 dark:bg-gray-600" aria-hidden="true" />
+          Expenditure
+        </span>
+      </div>
+    </div>
+  );
+}
diff --git a/components/ui/QrCodeModal.tsx b/components/ui/QrCodeModal.tsx
index dbccf19..a1f0ab8 100644
--- a/components/ui/QrCodeModal.tsx
+++ b/components/ui/QrCodeModal.tsx
@@ -5,8 +5,15 @@ import qrcode from "qrcode-generator";
 import { Modal } from "@/components/ui/Modal";
 
 interface QrCodeModalProps {
-  /** The address encoded into the QR code. */
-  address: string;
+  /** The address encoded into the QR code (legacy prop, kept for backwards compat). */
+  address?: string;
+  /**
+   * Generic payload encoded into the QR code (e.g. a stream claim URL).
+   * Takes precedence over `address` when both are provided (#688).
+   */
+  value?: string;
+  /** Modal title. Defaults to "Scan address" for address codes. */
+  title?: string;
   onClose: () => void;
 }
 
@@ -21,11 +28,14 @@ const CELL_SIZE = 4;
  * `createSvgTag` HTML-string output, so it needs no `dangerouslySetInnerHTML`
  * and can follow the app's light/dark theme.
  */
-export function QrCodeModal({ address, onClose }: QrCodeModalProps) {
+export function QrCodeModal({ address, value, title, onClose }: QrCodeModalProps) {
+  // #688 — generic share payload (stream claim URL) with legacy address fallback.
+  const payload = value ?? address ?? "";
+  const modalTitle = title ?? "Scan address";
   const modules = useMemo(() => {
     // Type number 0 = auto-select the smallest size that fits the data.
     const qr = qrcode(0, "M");
-    qr.addData(address);
+    qr.addData(payload);
     qr.make();
     const count = qr.getModuleCount();
     const cells: boolean[][] = [];
@@ -37,12 +47,12 @@ export function QrCodeModal({ address, onClose }: QrCodeModalProps) {
       cells.push(line);
     }
     return cells;
-  }, [address]);
+  }, [payload]);
 
   const size = modules.length * CELL_SIZE;
 
   return (
-    <Modal title="Scan address" onClose={onClose}>
+    <Modal title={modalTitle} onClose={onClose}>
       <div className="flex flex-col items-center gap-4">
         <div className="p-3 bg-white rounded">
           <svg
@@ -50,7 +60,7 @@ export function QrCodeModal({ address, onClose }: QrCodeModalProps) {
             width={size * 4}
             height={size * 4}
             role="img"
-            aria-label={`QR code for address ${address}`}
+            aria-label={`QR code for ${payload}`}
             className="block"
           >
             <rect x={0} y={0} width={size} height={size} fill="#fff" />
@@ -71,7 +81,7 @@ export function QrCodeModal({ address, onClose }: QrCodeModalProps) {
           </svg>
         </div>
         <p className="font-mono text-xs text-center break-all text-gray-500 dark:text-gray-400">
-          {address}
+          {payload}
         </p>
       </div>
     </Modal>
diff --git a/lib/custom-rpc.ts b/lib/custom-rpc.ts
new file mode 100644
index 0000000..739054f
--- /dev/null
+++ b/lib/custom-rpc.ts
@@ -0,0 +1,108 @@
+/**
+ * Custom Soroban RPC endpoint override (#691).
+ *
+ * Developers running a local sandbox (`http://localhost:8000`) or a private
+ * QuickNode/Triton node can override the preset network RPC URL from the
+ * Settings page. The override is stored in localStorage and takes precedence
+ * in `lib/env.ts#getRpcUrl` until cleared.
+ */
+
+export const CUSTOM_RPC_STORAGE_KEY = "conduit:custom-rpc";
+
+export function isValidRpcUrl(url: string): boolean {
+  const trimmed = url.trim();
+  if (!trimmed) return false;
+  try {
+    const parsed = new URL(trimmed);
+    return parsed.protocol === "http:" || parsed.protocol === "https:";
+  } catch {
+    return false;
+  }
+}
+
+/** Return the saved custom RPC override, or null when unset/invalid. */
+export function getCustomRpcUrl(): string | null {
+  if (typeof window === "undefined") return null;
+  try {
+    const raw = localStorage.getItem(CUSTOM_RPC_STORAGE_KEY);
+    if (!raw) return null;
+    const trimmed = raw.trim();
+    return trimmed && isValidRpcUrl(trimmed) ? trimmed : null;
+  } catch {
+    return null;
+  }
+}
+
+export function saveCustomRpcUrl(url: string): void {
+  const trimmed = url.trim();
+  if (!isValidRpcUrl(trimmed)) {
+    throw new Error("Enter a valid http(s) RPC URL.");
+  }
+  try {
+    localStorage.setItem(CUSTOM_RPC_STORAGE_KEY, trimmed);
+  } catch {
+    // Storage can be unavailable in private browsing or embedded webviews.
+  }
+}
+
+export function clearCustomRpcUrl(): void {
+  try {
+    localStorage.removeItem(CUSTOM_RPC_STORAGE_KEY);
+  } catch {
+    /* ignore */
+  }
+}
+
+export interface RpcPingResult {
+  ok: boolean;
+  latencyMs: number | null;
+  error?: string;
+}
+
+/**
+ * Validate an RPC endpoint by POSTing a lightweight `getHealth` JSON-RPC call
+ * and measuring round-trip latency. Never throws — failures are returned as
+ * `{ ok: false }` so the Settings UI can render them inline.
+ */
+export async function pingRpcEndpoint(
+  url: string,
+  timeoutMs = 10_000,
+): Promise<RpcPingResult> {
+  const trimmed = url.trim();
+  if (!isValidRpcUrl(trimmed)) {
+    return { ok: false, latencyMs: null, error: "Enter a valid http(s) RPC URL." };
+  }
+  const controller = new AbortController();
+  const timer = setTimeout(() => controller.abort(), timeoutMs);
+  const started = typeof performance !== "undefined" ? performance.now() : Date.now();
+  try {
+    const res = await fetch(trimmed, {
+      method: "POST",
+      headers: { "Content-Type": "application/json" },
+      body: JSON.stringify({ jsonrpc: "2.0", id: 1, method: "getHealth" }),
+      signal: controller.signal,
+    });
+    const ended = typeof performance !== "undefined" ? performance.now() : Date.now();
+    const latencyMs = Math.round(ended - started);
+    if (!res.ok) {
+      return { ok: false, latencyMs, error: `HTTP ${res.status} from RPC endpoint.` };
+    }
+    // A well-formed JSON-RPC response (even an error payload) proves the
+    // endpoint is reachable and speaking RPC. Only a transport failure fails.
+    await res.text().catch(() => "");
+    return { ok: true, latencyMs };
+  } catch (e) {
+    const ended = typeof performance !== "undefined" ? performance.now() : Date.now();
+    const latencyMs = Math.round(ended - started);
+    if (e instanceof Error && e.name === "AbortError") {
+      return { ok: false, latencyMs: null, error: `Timed out after ${timeoutMs} ms.` };
+    }
+    return {
+      ok: false,
+      latencyMs: null,
+      error: e instanceof Error ? e.message : "Could not reach the RPC endpoint.",
+    };
+  } finally {
+    clearTimeout(timer);
+  }
+}
diff --git a/lib/env.ts b/lib/env.ts
index 468113b..afbf588 100644
--- a/lib/env.ts
+++ b/lib/env.ts
@@ -13,6 +13,7 @@
  */
 
 import { loadSelectedNetwork } from './network-storage';
+import { CUSTOM_RPC_STORAGE_KEY, isValidRpcUrl } from './custom-rpc';
 
 function required(name: string): string {
   const value = process.env[name];
@@ -27,11 +28,18 @@ function required(name: string): string {
 /**
  * Return the RPC URL for the currently selected network.
  *
- * If the user has selected a known network (testnet/mainnet/local) from
- * settings, its well-known RPC URL is used. Otherwise falls back to
- * NEXT_PUBLIC_SOROBAN_RPC_URL so a custom/deployed URL can still be set.
+ * Precedence: an explicit custom override saved from Settings (#691) wins,
+ * then NEXT_PUBLIC_SOROBAN_RPC_URL, then the selected preset's well-known URL.
  */
 export function getRpcUrl(): string {
+  try {
+    if (typeof window !== 'undefined') {
+      const custom = window.localStorage.getItem(CUSTOM_RPC_STORAGE_KEY);
+      if (custom && isValidRpcUrl(custom)) return custom.trim();
+    }
+  } catch {
+    /* storage unavailable — fall through to presets */
+  }
   const selected = loadSelectedNetwork();
   return process.env['NEXT_PUBLIC_SOROBAN_RPC_URL'] || selected.rpcUrl;
 }
diff --git a/lib/profile-analytics.ts b/lib/profile-analytics.ts
new file mode 100644
index 0000000..c675bd5
--- /dev/null
+++ b/lib/profile-analytics.ts
@@ -0,0 +1,92 @@
+import type { StreamInfo } from "@/lib/stream";
+
+export const CASHFLOW_WINDOW_DAYS = 30;
+const DAY_S = 86_400;
+
+export interface CashflowStream {
+  info: StreamInfo;
+  /** "incoming" = user is recipient, "outgoing" = user is sender */
+  direction: "incoming" | "outgoing";
+}
+
+export interface DailyFlow {
+  /** Unix seconds at UTC midnight starting this bucket */
+  dayStart: number;
+  /** Short label, e.g. "Sep 12" */
+  label: string;
+  incoming: bigint;
+  outgoing: bigint;
+}
+
+export interface CashflowSummary {
+  totalIncoming: bigint;
+  totalOutgoing: bigint;
+  net: bigint;
+  daily: DailyFlow[];
+}
+
+/** Floor a unix timestamp to UTC midnight. */
+export function startOfUtcDay(ts: number): number {
+  return Math.floor(ts / DAY_S) * DAY_S;
+}
+
+/**
+ * Aggregate per-day streamed volume over the trailing `days` window ending at
+ * `nowSeconds` (#690).
+ *
+ * Volume for a stream on a given day is `ratePerSecond × overlapped seconds`
+ * between the stream's [startTime, effectiveEnd] interval and the day bucket,
+ * where effectiveEnd is `min(endTime || now, now)`. Cancelled/ended streams
+ * naturally contribute zero after they stop. Pause skew is intentionally
+ * ignored — analytics are an estimate, not settlement accounting.
+ */
+export function computeCashflow(
+  streams: CashflowStream[],
+  nowSeconds: number,
+  days: number = CASHFLOW_WINDOW_DAYS,
+): CashflowSummary {
+  const todayStart = startOfUtcDay(nowSeconds);
+  const windowStart = todayStart - (days - 1) * DAY_S;
+
+  const daily: DailyFlow[] = Array.from({ length: days }, (_, i) => {
+    const dayStart = windowStart + i * DAY_S;
+    return {
+      dayStart,
+      label: new Date(dayStart * 1000).toLocaleDateString("en-US", {
+        timeZone: "UTC",
+        month: "short",
+        day: "numeric",
+      }),
+      incoming: 0n,
+      outgoing: 0n,
+    };
+  });
+
+  let totalIncoming = 0n;
+  let totalOutgoing = 0n;
+
+  for (const { info, direction } of streams) {
+    if (info.ratePerSecond <= 0n) continue;
+    const streamStart = info.startTime;
+    const streamEnd = info.endTime > 0 ? Math.min(info.endTime, nowSeconds) : nowSeconds;
+    if (streamEnd <= streamStart) continue;
+    // Skip streams that ended before the window or start in the future.
+    if (streamEnd <= windowStart || streamStart >= todayStart + DAY_S) continue;
+
+    for (const bucket of daily) {
+      const bucketEnd = bucket.dayStart + DAY_S;
+      const overlap = Math.min(streamEnd, bucketEnd) - Math.max(streamStart, bucket.dayStart);
+      if (overlap <= 0) continue;
+      const volume = info.ratePerSecond * BigInt(Math.floor(overlap));
+      if (direction === "incoming") {
+        bucket.incoming += volume;
+        totalIncoming += volume;
+      } else {
+        bucket.outgoing += volume;
+        totalOutgoing += volume;
+      }
+    }
+  }
+
+  return { totalIncoming, totalOutgoing, net: totalIncoming - totalOutgoing, daily };
+}