diff --git a/client/components/CalendarFeedManager.jsx b/client/components/CalendarFeedManager.tsx
similarity index 82%
rename from client/components/CalendarFeedManager.jsx
rename to client/components/CalendarFeedManager.tsx
index 36cc361..0c564ec 100644
--- a/client/components/CalendarFeedManager.jsx
+++ b/client/components/CalendarFeedManager.tsx
@@ -1,13 +1,27 @@
-import React, { useCallback, useEffect, useState } from 'react';
+import { useCallback, useEffect, useState, type ReactNode } from 'react';
 import { Link } from 'react-router-dom';
 import { CalendarDays, Copy, Eye, KeyRound, RefreshCw, ShieldOff, Settings2 } from 'lucide-react';
 import { toast } from 'sonner';
 import { api } from '@/api';
-import { cn } from '@/lib/utils';
+import { cn, errMessage } from '@/lib/utils';
 import { Button } from '@/components/ui/button';
 import { Input } from '@/components/ui/input';
 
-function PlatformNote({ title, children }) {
+interface CalFeed {
+  active?: boolean;
+  feed_url?: string;
+  last_used_at?: string | null;
+}
+
+interface CalEvent {
+  uid: string;
+  name?: string;
+  due_date?: string;
+  cycle_type?: string;
+  amount?: number;
+}
+
+function PlatformNote({ title, children }: { title: ReactNode; children: ReactNode }) {
   return (
     <div className="rounded-md bg-muted/35 p-3">
       <p className="font-medium text-foreground">{title}</p>
@@ -16,25 +30,25 @@ function PlatformNote({ title, children }) {
   );
 }
 
-export function CalendarFeedManager({ compact = false, showManageLink = false }) {
-  const [feed, setFeed] = useState(null);
-  const [preview, setPreview] = useState([]);
+export function CalendarFeedManager({ compact = false, showManageLink = false }: { compact?: boolean; showManageLink?: boolean }) {
+  const [feed, setFeed] = useState<CalFeed | null>(null);
+  const [preview, setPreview] = useState<CalEvent[]>([]);
   const [loading, setLoading] = useState(true);
-  const [busy, setBusy] = useState(null);
+  const [busy, setBusy] = useState<string | null>(null);
 
   const loadFeed = useCallback(async () => {
     setLoading(true);
     try {
-      const data = await api.calendarFeed();
+      const data = await api.calendarFeed() as CalFeed;
       setFeed(data);
       if (data?.active) {
-        const nextPreview = await api.calendarFeedPreview(10);
+        const nextPreview = await api.calendarFeedPreview(10) as { events?: CalEvent[] };
         setPreview(nextPreview.events || []);
       } else {
         setPreview([]);
       }
     } catch (err) {
-      toast.error(err.message || 'Failed to load calendar feed.');
+      toast.error(errMessage(err, 'Failed to load calendar feed.'));
     } finally {
       setLoading(false);
     }
@@ -47,13 +61,13 @@ export function CalendarFeedManager({ compact = false, showManageLink = false })
   async function createFeed() {
     setBusy('create');
     try {
-      const data = await api.createCalendarFeed();
+      const data = await api.createCalendarFeed() as CalFeed;
       setFeed(data);
-      const nextPreview = await api.calendarFeedPreview(10);
+      const nextPreview = await api.calendarFeedPreview(10) as { events?: CalEvent[] };
       setPreview(nextPreview.events || []);
       toast.success('Calendar feed created.');
     } catch (err) {
-      toast.error(err.message || 'Failed to create calendar feed.');
+      toast.error(errMessage(err, 'Failed to create calendar feed.'));
     } finally {
       setBusy(null);
     }
@@ -72,13 +86,13 @@ export function CalendarFeedManager({ compact = false, showManageLink = false })
   async function regenerateFeed() {
     setBusy('regenerate');
     try {
-      const data = await api.regenerateCalendarFeed();
+      const data = await api.regenerateCalendarFeed() as CalFeed;
       setFeed(data);
-      const nextPreview = await api.calendarFeedPreview(10);
+      const nextPreview = await api.calendarFeedPreview(10) as { events?: CalEvent[] };
       setPreview(nextPreview.events || []);
       toast.success('Calendar feed regenerated. Update any subscribed calendars with the new URL.');
     } catch (err) {
-      toast.error(err.message || 'Failed to regenerate calendar feed.');
+      toast.error(errMessage(err, 'Failed to regenerate calendar feed.'));
     } finally {
       setBusy(null);
     }
@@ -87,12 +101,12 @@ export function CalendarFeedManager({ compact = false, showManageLink = false })
   async function revokeFeed() {
     setBusy('revoke');
     try {
-      const data = await api.revokeCalendarFeed();
+      const data = await api.revokeCalendarFeed() as CalFeed;
       setFeed(data);
       setPreview([]);
       toast.success('Calendar feed revoked.');
     } catch (err) {
-      toast.error(err.message || 'Failed to revoke calendar feed.');
+      toast.error(errMessage(err, 'Failed to revoke calendar feed.'));
     } finally {
       setBusy(null);
     }
@@ -150,13 +164,13 @@ export function CalendarFeedManager({ compact = false, showManageLink = false })
           </div>
 
           <div className="flex flex-col gap-2 sm:flex-row">
-            <Input value={feed.feed_url} readOnly className="min-w-0 flex-1 font-mono text-xs" aria-label="Calendar feed URL" />
+            <Input value={feed?.feed_url ?? ''} readOnly className="min-w-0 flex-1 font-mono text-xs" aria-label="Calendar feed URL" />
             <Button size="sm" variant="outline" onClick={copyFeedUrl} className="gap-2">
               <Copy className="h-3.5 w-3.5" />
               Copy URL
             </Button>
             <Button asChild size="sm" variant="outline" className="gap-2">
-              <a href={feed.feed_url} target="_blank" rel="noreferrer">
+              <a href={feed?.feed_url} target="_blank" rel="noreferrer">
                 <Eye className="h-3.5 w-3.5" />
                 Preview ICS
               </a>
@@ -182,7 +196,7 @@ export function CalendarFeedManager({ compact = false, showManageLink = false })
             <div className="flex flex-col gap-1 border-b border-border/60 px-3 py-2 sm:flex-row sm:items-center sm:justify-between">
               <p className="text-xs font-semibold uppercase tracking-wide text-muted-foreground">Next events that will appear</p>
               <span className="text-xs text-muted-foreground">
-                Last fetched: {feed.last_used_at ? new Date(feed.last_used_at).toLocaleString() : 'Not yet'}
+                Last fetched: {feed?.last_used_at ? new Date(feed.last_used_at).toLocaleString() : 'Not yet'}
               </span>
             </div>
             <div className="divide-y divide-border/50">
diff --git a/client/components/IncomeBreakdownModal.jsx b/client/components/IncomeBreakdownModal.tsx
similarity index 83%
rename from client/components/IncomeBreakdownModal.jsx
rename to client/components/IncomeBreakdownModal.tsx
index 2b0fb30..3ec7f5e 100644
--- a/client/components/IncomeBreakdownModal.jsx
+++ b/client/components/IncomeBreakdownModal.tsx
@@ -1,33 +1,60 @@
-import React, { useState, useEffect, useCallback } from 'react';
+import { useState, useEffect, useCallback } from 'react';
 import { toast } from 'sonner';
-import { formatUSD } from '@/lib/money';
-import { TrendingUp, EyeOff, Eye, ArrowRight, Loader2 } from 'lucide-react';
+import { formatUSD, asDollars, type Dollars } from '@/lib/money';
+import { TrendingUp, EyeOff, Eye, Loader2 } from 'lucide-react';
 import { api } from '@/api';
+import { errMessage } from '@/lib/utils';
 import { Button } from '@/components/ui/button';
 import {
   Dialog, DialogContent, DialogHeader, DialogTitle, DialogDescription,
 } from '@/components/ui/dialog';
 
-function fmt(n) {
+function fmt(n: Parameters<typeof formatUSD>[0]): string {
   return formatUSD(n);
 }
 
-export default function IncomeBreakdownModal({ open, onClose, year, month, bankTracking }) {
-  const [transactions, setTransactions] = useState([]);
+interface IncomeTx {
+  id: number | string;
+  payee?: string | null;
+  date?: string | null;
+  amount: Dollars;
+  ignored?: boolean;
+}
+
+interface IncomeBt {
+  enabled?: boolean;
+  org_name?: string | null;
+  account_name?: string | null;
+  balance?: Dollars;
+  pending_payments?: Dollars;
+  pending_days?: number;
+  effective_balance?: Dollars;
+}
+
+interface IncomeBreakdownModalProps {
+  open: boolean;
+  onClose: () => void;
+  year: number;
+  month: number;
+  bankTracking?: IncomeBt | null;
+}
+
+export default function IncomeBreakdownModal({ open, onClose, year, month, bankTracking }: IncomeBreakdownModalProps) {
+  const [transactions, setTransactions] = useState<IncomeTx[]>([]);
   const [loading,      setLoading]      = useState(false);
   const [loadError,    setLoadError]    = useState('');
   const [showIgnored,  setShowIgnored]  = useState(false);
-  const [actionId,     setActionId]     = useState(null); // tx being acted on
+  const [actionId,     setActionId]     = useState<number | string | null>(null);
 
   const load = useCallback(async () => {
     if (!open) return;
     setLoading(true);
     setLoadError('');
     try {
-      const d = await api.spendingIncome({ year, month, include_ignored: showIgnored ? 'true' : undefined, limit: 100 });
+      const d = await api.spendingIncome({ year, month, include_ignored: showIgnored ? 'true' : undefined, limit: 100 }) as { transactions?: IncomeTx[] };
       setTransactions(d.transactions || []);
     } catch (err) {
-      const msg = err.message || 'Failed to load income transactions';
+      const msg = errMessage(err, 'Failed to load income transactions');
       setLoadError(msg);
       toast.error(msg);
     } finally {
@@ -37,13 +64,13 @@ export default function IncomeBreakdownModal({ open, onClose, year, month, bankT
 
   useEffect(() => { load(); }, [load]);
 
-  const handleIgnore = async (tx) => {
+  const handleIgnore = async (tx: IncomeTx) => {
     setActionId(tx.id);
     try {
       await api.ignoreTransaction(tx.id);
       toast.success(`"${tx.payee}" marked as excluded`);
     } catch (err) {
-      toast.error(err.message || 'Failed to exclude transaction');
+      toast.error(errMessage(err, 'Failed to exclude transaction'));
       setActionId(null);
       return; // don't reload if the action itself failed
     }
@@ -51,13 +78,13 @@ export default function IncomeBreakdownModal({ open, onClose, year, month, bankT
     await load(); // reload outside the action try so load errors are surfaced separately
   };
 
-  const handleUnignore = async (tx) => {
+  const handleUnignore = async (tx: IncomeTx) => {
     setActionId(tx.id);
     try {
       await api.unignoreTransaction(tx.id);
       toast.success(`"${tx.payee}" restored as income`);
     } catch (err) {
-      toast.error(err.message || 'Failed to restore transaction');
+      toast.error(errMessage(err, 'Failed to restore transaction'));
       setActionId(null);
       return;
     }
@@ -67,7 +94,7 @@ export default function IncomeBreakdownModal({ open, onClose, year, month, bankT
 
   const active   = transactions.filter(t => !t.ignored);
   const ignored  = transactions.filter(t => t.ignored);
-  const total    = active.reduce((s, t) => s + t.amount, 0);
+  const total    = asDollars(active.reduce((s, t) => s + t.amount, 0));
 
   const bt = bankTracking || {};
 
@@ -91,7 +118,7 @@ export default function IncomeBreakdownModal({ open, onClose, year, month, bankT
               <span className="text-muted-foreground">{bt.org_name || bt.account_name || 'Bank'} balance</span>
               <span className="font-mono font-semibold">{fmt(bt.balance)}</span>
             </div>
-            {bt.pending_payments > 0 && (
+            {(bt.pending_payments ?? 0) > 0 && (
               <div className="flex items-center justify-between text-muted-foreground">
                 <span>Pending payments ({bt.pending_days}d window)</span>
                 <span className="font-mono text-destructive">−{fmt(bt.pending_payments)}</span>
diff --git a/client/components/MobileBillRow.jsx b/client/components/MobileBillRow.tsx
similarity index 85%
rename from client/components/MobileBillRow.jsx
rename to client/components/MobileBillRow.tsx
index 0cb863c..0e8da78 100644
--- a/client/components/MobileBillRow.jsx
+++ b/client/components/MobileBillRow.tsx
@@ -3,15 +3,28 @@ import { ArrowDown, ArrowUp, Copy, GripVertical, History } from 'lucide-react';
 import { Button } from '@/components/ui/button';
 import { cn } from '@/lib/utils';
 import { scheduleLabel } from '@/lib/billingSchedule';
+import type { Bill } from '@/types';
+import type { DragProps, MoveControls } from '@/components/tracker/MobileTrackerRow';
 
-function hasHistoricalVisibility(bill) {
+function hasHistoricalVisibility(bill: Bill): boolean {
   const visibility = bill.history_visibility;
-  return !!bill.has_history_ranges || (visibility && visibility !== 'default');
+  return !!bill.has_history_ranges || (!!visibility && visibility !== 'default');
 }
 
-export const MobileBillRow = React.memo(function MobileBillRow({ bill, onEdit, onToggle, onDelete, onHistory, onDuplicate, moveControls, dragProps }) {
+interface MobileBillRowProps {
+  bill: Bill;
+  onEdit?: (id: number) => void;
+  onToggle?: (bill: Bill) => void;
+  onDelete?: (bill: Bill) => void;
+  onHistory?: (bill: Bill) => void;
+  onDuplicate?: (bill: Bill) => void;
+  moveControls?: MoveControls;
+  dragProps?: DragProps;
+}
+
+export const MobileBillRow = React.memo(function MobileBillRow({ bill, onEdit, onToggle, onDelete, onHistory, onDuplicate, moveControls, dragProps }: MobileBillRowProps) {
   const hasHistory = useMemo(() => hasHistoricalVisibility(bill), [bill]);
-  
+
   const statusClass = useMemo(() => {
     return cn(
       'rounded px-1.5 py-0.5 text-[10px] font-semibold uppercase tracking-wide',
@@ -33,11 +46,11 @@ export const MobileBillRow = React.memo(function MobileBillRow({ bill, onEdit, o
   return (
     <div
       draggable={dragProps?.draggable}
-      onDragStart={dragProps?.onDragStart}
-      onDragEnter={dragProps?.onDragEnter}
-      onDragOver={dragProps?.onDragOver}
-      onDragEnd={dragProps?.onDragEnd}
-      onDrop={dragProps?.onDrop}
+      onDragStart={dragProps?.onDragStart as React.ComponentProps<'div'>['onDragStart']}
+      onDragEnter={dragProps?.onDragEnter as React.ComponentProps<'div'>['onDragEnter']}
+      onDragOver={dragProps?.onDragOver as React.ComponentProps<'div'>['onDragOver']}
+      onDragEnd={dragProps?.onDragEnd as React.ComponentProps<'div'>['onDragEnd']}
+      onDrop={dragProps?.onDrop as React.ComponentProps<'div'>['onDrop']}
       className={cn(
         'group rounded-xl border border-border/80 bg-card/90 p-3 shadow-sm shadow-black/10',
         dragProps?.isDragging && 'opacity-45',
@@ -103,18 +116,18 @@ export const MobileBillRow = React.memo(function MobileBillRow({ bill, onEdit, o
             <span className={statusClass}>
               {bill.active ? 'Active' : 'Inactive'}
             </span>
-            {bill.autopay_enabled && (
+            {bill.autopay_enabled ? (
               <span className="rounded bg-emerald-500/20 px-1.5 py-0.5 text-[10px] font-semibold text-emerald-300">AP</span>
-            )}
-            {bill.has_2fa && (
+            ) : null}
+            {bill.has_2fa ? (
               <span className="rounded bg-violet-500/20 px-1.5 py-0.5 text-[10px] font-semibold text-violet-300">2FA</span>
-            )}
-            {(bill.has_merchant_rule || bill.has_linked_transactions) && (
+            ) : null}
+            {(bill.has_merchant_rule || bill.has_linked_transactions) ? (
               <span className="rounded border border-emerald-500/25 bg-emerald-500/10 px-1.5 py-0.5 text-[10px] font-semibold text-emerald-600 dark:text-emerald-400" title="Linked to bank transactions">L</span>
-            )}
-            {bill.is_subscription && (
+            ) : null}
+            {bill.is_subscription ? (
               <span className="rounded border border-indigo-500/25 bg-indigo-500/10 px-1.5 py-0.5 text-[10px] font-semibold text-indigo-600 dark:text-indigo-300">S</span>
-            )}
+            ) : null}
           </div>
         </div>
 
diff --git a/client/components/snowball/PayoffChart.jsx b/client/components/snowball/PayoffChart.jsx
deleted file mode 100644
index 6faee4f..0000000
--- a/client/components/snowball/PayoffChart.jsx
+++ /dev/null
@@ -1,145 +0,0 @@
-import React from 'react';
-import { formatUSD } from '@/lib/money';
-
-const W = 720;
-const H = 300;
-const PAD = { left: 68, right: 24, top: 20, bottom: 56 };
-const CW = W - PAD.left - PAD.right;
-const CH = H - PAD.top - PAD.bottom;
-
-function money(v) {
-  const n = Number(v) || 0;
-  if (n >= 1000) return `$${(n / 1000).toFixed(0)}k`;
-  return `$${n.toFixed(0)}`;
-}
-
-function fullMoney(v) {
-  return formatUSD(v);
-}
-
-function buildPoints(track, startBalance, maxMonths) {
-  const all = [{ month: 0, balance: startBalance }, ...track];
-  return all.map(({ month, balance }) => ({
-    x: PAD.left + (month / maxMonths) * CW,
-    y: PAD.top + CH - (balance / startBalance) * CH,
-    month,
-    balance,
-  }));
-}
-
-function toLine(pts) {
-  return pts.map(p => `${p.x.toFixed(1)},${p.y.toFixed(1)}`).join(' ');
-}
-
-export default function PayoffChart({ minTrack = [], currentTrack = [], simTrack = [], startBalance = 1 }) {
-  const maxMonths = Math.max(minTrack.length, currentTrack.length, simTrack.length, 12);
-  const bal = Math.max(startBalance, 1);
-
-  const minPts     = buildPoints(minTrack,     bal, maxMonths);
-  const currentPts = buildPoints(currentTrack, bal, maxMonths);
-  const simPts     = buildPoints(simTrack,     bal, maxMonths);
-
-  const xStep = maxMonths <= 24 ? 6 : maxMonths <= 60 ? 12 : 24;
-  const xLabels = [];
-  for (let m = xStep; m <= maxMonths; m += xStep) {
-    xLabels.push(m);
-  }
-
-  const yTicks = [0, 0.25, 0.5, 0.75, 1];
-
-  const showCurrent = currentTrack.length > 0 &&
-    currentTrack.some((c, i) => (minTrack[i]?.balance ?? null) !== c.balance);
-
-  return (
-    <div className="w-full overflow-hidden rounded-xl border border-border/60 bg-background/60">
-      <svg viewBox={`0 0 ${W} ${H}`} role="img" aria-label="Loan payoff chart" className="h-auto w-full">
-
-        {/* Grid + Y axis */}
-        {yTicks.map(tick => {
-          const y = PAD.top + CH - tick * CH;
-          return (
-            <g key={tick}>
-              <line x1={PAD.left} x2={PAD.left + CW} y1={y} y2={y}
-                stroke="currentColor" opacity="0.08" strokeWidth="1" />
-              <text x={PAD.left - 6} y={y + 4} fontSize="11" fill="currentColor"
-                opacity="0.5" textAnchor="end">
-                {money(bal * tick)}
-              </text>
-            </g>
-          );
-        })}
-
-        {/* X axis labels */}
-        {xLabels.map(m => {
-          const x = PAD.left + (m / maxMonths) * CW;
-          return (
-            <text key={m} x={x} y={H - 38} fontSize="11" fill="currentColor"
-              opacity="0.5" textAnchor="middle">
-              {m}mo
-            </text>
-          );
-        })}
-
-        {/* X axis baseline */}
-        <line x1={PAD.left} x2={PAD.left + CW} y1={PAD.top + CH} y2={PAD.top + CH}
-          stroke="currentColor" opacity="0.12" strokeWidth="1" />
-
-        {/* Min-only track (slate dashed) */}
-        {minPts.length > 1 && (
-          <polyline points={toLine(minPts)} fill="none"
-            stroke="#94a3b8" strokeWidth="1.5"
-            strokeDasharray="6,4" strokeLinecap="round" strokeLinejoin="round"
-          />
-        )}
-
-        {/* Current snowball plan (indigo dashed) */}
-        {showCurrent && currentPts.length > 1 && (
-          <polyline points={toLine(currentPts)} fill="none"
-            stroke="#818cf8" strokeWidth="1.5"
-            strokeDasharray="9,5" strokeLinecap="round" strokeLinejoin="round"
-          />
-        )}
-
-        {/* Simulation track (amber solid, prominent) */}
-        {simPts.length > 1 && (
-          <>
-            <polyline points={toLine(simPts)} fill="none"
-              stroke="#f59e0b" strokeWidth="3"
-              strokeLinecap="round" strokeLinejoin="round"
-            />
-            {/* Endpoint dot */}
-            {(() => {
-              const last = simPts[simPts.length - 1];
-              return <circle cx={last.x} cy={last.y} r="4" fill="#f59e0b" />;
-            })()}
-          </>
-        )}
-
-        {/* Tooltips at 6-month intervals on sim track */}
-        {simPts.filter(p => p.month > 0 && p.month % 6 === 0).map(p => (
-          <circle key={p.month} cx={p.x} cy={p.y} r="3" fill="#f59e0b" opacity="0.7">
-            <title>{`Month ${p.month}: ${fullMoney(p.balance)} remaining`}</title>
-          </circle>
-        ))}
-
-        {/* Legend */}
-        <g transform={`translate(${PAD.left}, ${H - 22})`} fontSize="11" fill="currentColor" opacity="0.7">
-          <line x1="0" x2="16" y1="0" y2="0" stroke="#94a3b8" strokeWidth="1.5" strokeDasharray="4,3" />
-          <text x="20" y="4">Min only</text>
-
-          {showCurrent && (
-            <>
-              <line x1="80" x2="96" y1="0" y2="0" stroke="#818cf8" strokeWidth="1.5" strokeDasharray="6,4" />
-              <text x="100" y="4">Snowball plan</text>
-            </>
-          )}
-
-          <line x1={showCurrent ? 198 : 80} x2={showCurrent ? 214 : 96} y1="0" y2="0"
-            stroke="#f59e0b" strokeWidth="2.5" />
-          <text x={showCurrent ? 218 : 100} y="4">Simulation</text>
-        </g>
-
-      </svg>
-    </div>
-  );
-}