diff --git a/frontend/src/components/inventory/useInventorySearch.ts b/frontend/src/components/inventory/useInventorySearch.ts
new file mode 100644
index 00000000..a96a0c30
--- /dev/null
+++ b/frontend/src/components/inventory/useInventorySearch.ts
@@ -0,0 +1,118 @@
+import { useCallback, useEffect, useRef, useState } from 'react';
+import { DEFAULT_FILTERS, type SearchFilters, type SearchResponse } from './types';
+import { PAGE_SIZE } from './constants';
+
+/** Serialize only the keys that differ from defaults, as a compact q= JSON param. */
+function filtersToUrl(f: SearchFilters): void {
+  const diff: Partial<SearchFilters> = {};
+  for (const k of Object.keys(DEFAULT_FILTERS) as Array<keyof SearchFilters>) {
+    if (JSON.stringify(f[k]) !== JSON.stringify(DEFAULT_FILTERS[k])) (diff as any)[k] = f[k];
+  }
+  const url = new URL(window.location.href);
+  url.searchParams.set('view', 'inventory');
+  if (Object.keys(diff).length) url.searchParams.set('q', JSON.stringify(diff));
+  else url.searchParams.delete('q');
+  window.history.replaceState(null, '', url);
+}
+
+function filtersFromUrl(): SearchFilters {
+  try {
+    const q = new URLSearchParams(window.location.search).get('q');
+    if (!q) return DEFAULT_FILTERS;
+    return { ...DEFAULT_FILTERS, ...JSON.parse(q) };
+  } catch {
+    return DEFAULT_FILTERS;
+  }
+}
+
+export function buildParams(f: SearchFilters): URLSearchParams {
+  const p = new URLSearchParams();
+  if (f.characters === 'all') p.set('include_all_characters', 'true');
+  else if (f.characters.length === 1) p.set('character', f.characters[0]);
+  else p.set('characters', f.characters.join(','));
+
+  if (f.text) p.set('text', f.text);
+  switch (f.itemType) {
+    case 'armor': p.set('armor_only', 'true'); break;
+    case 'jewelry': p.set('jewelry_only', 'true'); break;
+    case 'clothing': p.set('clothing_only', 'true'); break;
+    case 'shirt': p.set('shirt_only', 'true'); break;
+    case 'pants': p.set('pants_only', 'true'); break;
+    case 'weapon':
+      p.set('weapon_only', 'true');
+      if (f.weaponType) p.set('weapon_type', f.weaponType);
+      break;
+  }
+  if (f.slots.length) p.set('slot_names', f.slots.join(','));
+  if (f.cantrips.length) p.set('legendary_cantrips', f.cantrips.join(','));
+  if (f.spellContains) p.set('spell_contains', f.spellContains);
+  for (const [param, v] of Object.entries(f.ratings)) if (v !== '') p.set(param, String(v));
+  if (f.itemSet) p.set('item_set', f.itemSet);
+  if (f.equippedOnly) p.set('equipment_status', 'equipped');
+  if (f.bonded) p.set('bonded', 'true');
+  if (f.attuned) p.set('attuned', 'true');
+  if (f.rare) p.set('is_rare', 'true');
+  if (f.maxLevel !== '') p.set('max_level', String(f.maxLevel));
+  if (f.minValue !== '') p.set('min_value', String(f.minValue));
+  if (f.minWorkmanship !== '') p.set('min_workmanship', String(f.minWorkmanship));
+  if (f.maxBurden !== '') p.set('max_burden', String(f.maxBurden));
+  p.set('sort_by', f.sortBy);
+  p.set('sort_dir', f.sortDir);
+  p.set('page', String(f.page));
+  p.set('limit', String(PAGE_SIZE));
+  return p;
+}
+
+export interface InventorySearch {
+  filters: SearchFilters;
+  /** Patch filters; resets page to 1 unless the patch itself sets page. */
+  update: (patch: Partial<SearchFilters>) => void;
+  reset: () => void;
+  result: SearchResponse | null;
+  loading: boolean;
+  error: string | null;
+  queryMs: number | null;
+}
+
+export function useInventorySearch(): InventorySearch {
+  const [filters, setFilters] = useState<SearchFilters>(filtersFromUrl);
+  const [result, setResult] = useState<SearchResponse | null>(null);
+  const [loading, setLoading] = useState(false);
+  const [error, setError] = useState<string | null>(null);
+  const [queryMs, setQueryMs] = useState<number | null>(null);
+  const abortRef = useRef<AbortController | null>(null);
+
+  const update = useCallback((patch: Partial<SearchFilters>) => {
+    setFilters(prev => ({ ...prev, page: 'page' in patch ? prev.page : 1, ...patch }));
+  }, []);
+  const reset = useCallback(() => setFilters(DEFAULT_FILTERS), []);
+
+  useEffect(() => {
+    filtersToUrl(filters);
+    const timer = setTimeout(async () => {
+      abortRef.current?.abort();
+      const ctrl = new AbortController();
+      abortRef.current = ctrl;
+      setLoading(true);
+      const t0 = performance.now();
+      try {
+        const res = await fetch(`/api/inv/search/items?${buildParams(filters)}`, {
+          credentials: 'include', signal: ctrl.signal,
+        });
+        if (!res.ok) throw new Error(`search: HTTP ${res.status}`);
+        const data: SearchResponse = await res.json();
+        if (data.error) throw new Error(data.error);
+        setResult(data);
+        setError(null);
+        setQueryMs(Math.round(performance.now() - t0));
+      } catch (e: any) {
+        if (e?.name !== 'AbortError') setError(String(e?.message ?? e));
+      } finally {
+        if (abortRef.current === ctrl) setLoading(false);
+      }
+    }, 400);
+    return () => clearTimeout(timer);
+  }, [filters]);
+
+  return { filters, update, reset, result, loading, error, queryMs };
+}