diff --git a/client/components/tracker/FilterChip.jsx b/client/components/tracker/FilterChip.tsx
similarity index 66%
rename from client/components/tracker/FilterChip.jsx
rename to client/components/tracker/FilterChip.tsx
index 747568f..d689a91 100644
--- a/client/components/tracker/FilterChip.jsx
+++ b/client/components/tracker/FilterChip.tsx
@@ -1,6 +1,13 @@
+import type { ReactNode } from 'react';
 import { cn } from '@/lib/utils';
 
-export function FilterChip({ active, children, onClick }) {
+interface FilterChipProps {
+  active?: boolean;
+  children?: ReactNode;
+  onClick?: () => void;
+}
+
+export function FilterChip({ active, children, onClick }: FilterChipProps) {
   return (
     <button
       type="button"
diff --git a/client/components/tracker/PaymentProgress.jsx b/client/components/tracker/PaymentProgress.tsx
similarity index 87%
rename from client/components/tracker/PaymentProgress.jsx
rename to client/components/tracker/PaymentProgress.tsx
index 0ee7236..eb9e89f 100644
--- a/client/components/tracker/PaymentProgress.jsx
+++ b/client/components/tracker/PaymentProgress.tsx
@@ -1,7 +1,18 @@
 import { cn, fmt } from '@/lib/utils';
 import { paymentSummary } from '@/lib/trackerUtils';
+import type { Dollars } from '@/lib/money';
+import type { TrackerRow } from '@/types';
 
-export function PaymentProgress({ row, threshold, onOpen, onMarkFullAmount, compact = false, className }) {
+interface PaymentProgressProps {
+  row: TrackerRow;
+  threshold: Dollars;
+  onOpen?: () => void;
+  onMarkFullAmount?: () => void;
+  compact?: boolean;
+  className?: string;
+}
+
+export function PaymentProgress({ row, threshold, onOpen, onMarkFullAmount, compact = false, className }: PaymentProgressProps) {
   const summary = paymentSummary(row, threshold);
   const barTone = summary.remaining === 0
     ? 'bg-emerald-500'
diff --git a/client/components/tracker/StatusBadge.jsx b/client/components/tracker/StatusBadge.tsx
similarity index 87%
rename from client/components/tracker/StatusBadge.jsx
rename to client/components/tracker/StatusBadge.tsx
index b50aa66..e42cfe2 100644
--- a/client/components/tracker/StatusBadge.jsx
+++ b/client/components/tracker/StatusBadge.tsx
@@ -2,8 +2,16 @@ import React, { useMemo } from 'react';
 import { Loader2, AlertCircle } from 'lucide-react';
 import { cn } from '@/lib/utils';
 import { STATUS_META, isPaidStatus } from '@/lib/trackerUtils';
+import type { TrackerStatus } from '@/types';
 
-export const StatusBadge = React.memo(function StatusBadge({ status, clickable, onClick, loading }) {
+interface StatusBadgeProps {
+  status: TrackerStatus;
+  clickable?: boolean;
+  onClick?: () => void;
+  loading?: boolean;
+}
+
+export const StatusBadge = React.memo(function StatusBadge({ status, clickable, onClick, loading }: StatusBadgeProps) {
   const meta = useMemo(() => STATUS_META[status] || STATUS_META.upcoming, [status]);
 
   const isSkipped = status === 'skipped';
diff --git a/client/components/tracker/SummaryCards.jsx b/client/components/tracker/SummaryCards.tsx
similarity index 84%
rename from client/components/tracker/SummaryCards.jsx
rename to client/components/tracker/SummaryCards.tsx
index cc683b1..cce386f 100644
--- a/client/components/tracker/SummaryCards.jsx
+++ b/client/components/tracker/SummaryCards.tsx
@@ -1,7 +1,20 @@
-import { TrendingUp, AlertCircle, Clock, CheckCircle2, Settings2 } from 'lucide-react';
+import { TrendingUp, AlertCircle, Clock, CheckCircle2, Settings2, type LucideIcon } from 'lucide-react';
 import { cn, fmt } from '@/lib/utils';
+import type { Dollars } from '@/lib/money';
 
-const CARD_DEFS = {
+type CardType = 'starting' | 'paid' | 'remaining' | 'overdue';
+
+interface CardDef {
+  label: string;
+  icon: LucideIcon;
+  bar: string;
+  glow: string;
+  borderActive?: string;
+  valueClass: string;
+  activateWhen: (v: number) => boolean;
+}
+
+const CARD_DEFS: Record<CardType, CardDef> = {
   starting:  {
     label: 'Starting',
     icon: TrendingUp,
@@ -38,12 +51,17 @@ const CARD_DEFS = {
   },
 };
 
-export function TrendIndicator({ trend }) {
+interface TrendInfo {
+  direction: string;
+  percent_change: number;
+}
+
+export function TrendIndicator({ trend }: { trend?: TrendInfo | null }) {
   if (!trend) return null;
 
   const { direction, percent_change } = trend;
 
-  let icon, color, text;
+  let icon: string, color: string, text: string;
   switch (direction) {
     case 'up':
       icon = '↑';
@@ -73,7 +91,15 @@ export function TrendIndicator({ trend }) {
   );
 }
 
-export function SummaryCard({ type, value, onEdit, hint, label }) {
+interface SummaryCardProps {
+  type: CardType;
+  value?: Dollars;
+  onEdit?: () => void;
+  hint?: string;
+  label?: string;
+}
+
+export function SummaryCard({ type, value, onEdit, hint, label }: SummaryCardProps) {
   const def      = CARD_DEFS[type];
   const isActive = def.activateWhen(value || 0);
   const Icon     = def.icon;
@@ -118,7 +144,7 @@ export function SummaryCard({ type, value, onEdit, hint, label }) {
   );
 }
 
-export function TrendCard({ trend }) {
+export function TrendCard({ trend }: { trend?: TrendInfo | null }) {
   if (!trend) return null;
 
   return (