diff --git a/frontend/app/core/contexts/SearchContext.tsx b/frontend/app/core/contexts/SearchContext.tsx
index b444cb6..956ca34 100644
--- a/frontend/app/core/contexts/SearchContext.tsx
+++ b/frontend/app/core/contexts/SearchContext.tsx
@@ -1,4 +1,5 @@
 import { createContext, useState, useCallback, type ReactNode } from "react"
+import { useInvalidateServers } from "@/core/hooks/useInvalidateServers"
 
 interface SearchContextType {
     searchQuery: string
@@ -14,10 +15,14 @@ export { SearchContext }
 export function SearchProvider({ children }: { children: ReactNode }) {
     const [searchQuery, setSearchQuery] = useState("")
     const [refreshCounter, setRefreshCounter] = useState(0)
+    const invalidateServers = useInvalidateServers()
 
     const triggerRefresh = useCallback(() => {
         setRefreshCounter(prev => prev + 1)
-    }, [])
+        // Le nouveau serveur doit apparaître dans le Ctrl+K (SearchBar) et dans
+        // la home : on invalide les deux caches pour forcer un refetch client.
+        invalidateServers()
+    }, [invalidateServers])
 
     return (
         <SearchContext.Provider value={{ searchQuery, setSearchQuery, refreshCounter, triggerRefresh }}>
diff --git a/frontend/app/core/hooks/useInvalidateServers.ts b/frontend/app/core/hooks/useInvalidateServers.ts
new file mode 100644
index 0000000..13b6c9e
--- /dev/null
+++ b/frontend/app/core/hooks/useInvalidateServers.ts
@@ -0,0 +1,19 @@
+import { useCallback } from "react"
+import { useQueryClient } from "@tanstack/react-query"
+import { SERVERS_QUERY_KEY, SERVERS_SEARCH_QUERY_KEY } from "@/core/lib/query-keys"
+
+/**
+ * Retourne un callback qui invalide les caches globaux de la liste des
+ * serveurs (home + recherche Ctrl+K) pour forcer un refetch client.
+ *
+ * À appeler après toute mutation qui change la liste ou son contenu :
+ * ajout, suppression, renommage, changement d'IP/favicon, visibilité.
+ */
+export function useInvalidateServers() {
+    const queryClient = useQueryClient()
+
+    return useCallback(() => {
+        queryClient.invalidateQueries({ queryKey: SERVERS_QUERY_KEY })
+        queryClient.invalidateQueries({ queryKey: SERVERS_SEARCH_QUERY_KEY })
+    }, [queryClient])
+}
diff --git a/frontend/app/core/lib/query-keys.ts b/frontend/app/core/lib/query-keys.ts
new file mode 100644
index 0000000..a7c842f
--- /dev/null
+++ b/frontend/app/core/lib/query-keys.ts
@@ -0,0 +1,17 @@
+/**
+ * Clés TanStack Query partagées pour la liste des serveurs.
+ *
+ * Centralisées ici pour éviter les chaînes magiques dupliquées (typos,
+ * renommages partiels) : toute lecture/écriture/invalidation de ces caches
+ * doit passer par ces constantes.
+ */
+
+/** Liste globale des serveurs (home, `include_stats=true`), amorcée par le SSR. */
+export const SERVERS_QUERY_KEY = ["servers"] as const
+
+/**
+ * Préfixe du cache de la recherche Ctrl+K.
+ * La clé complète est `[..., refreshCounter]` ; l'invalidation par préfixe
+ * (sans `exact: true`) couvre toutes les générations.
+ */
+export const SERVERS_SEARCH_QUERY_KEY = ["servers-search"] as const
diff --git a/frontend/app/core/lib/utils.test.ts b/frontend/app/core/lib/utils.test.ts
new file mode 100644
index 0000000..81568dc
--- /dev/null
+++ b/frontend/app/core/lib/utils.test.ts
@@ -0,0 +1,48 @@
+import { describe, it, expect } from "vitest"
+import { registerTranslations } from "./i18n"
+import { formatDate, formatNumber } from "./utils"
+
+// Dictionnaires minimaux : formatDate ne dépend que de common.months et
+// common.dateFormat (même contrat que les locales réelles).
+registerTranslations("fr", {
+    common: {
+        months: {
+            0: "janvier",
+            8: "septembre",
+            9: "octobre",
+        },
+        dateFormat: "{{day}} {{month}} {{year}}",
+    },
+})
+
+describe("formatDate", () => {
+    // 13 octobre 2026 23:30 UTC : en Europe/Paris (UTC+2) il est déjà le 14,
+    // à Kiritimati (UTC+14) le 14 à 13:30. Avec des getters locaux, le HTML
+    // SSR (UTC) et le rendu client divergeaient -> erreur d'hydratation #418.
+    const nearMidnightUtc = Date.UTC(2026, 9, 13, 23, 30)
+
+    it("renders the same UTC calendar date regardless of runtime timezone", () => {
+        const outputs = new Set<string>()
+        for (const tz of ["UTC", "Europe/Paris", "America/New_York", "Pacific/Kiritimati", "Australia/Sydney"]) {
+            process.env.TZ = tz
+            outputs.add(formatDate(nearMidnightUtc, "fr"))
+        }
+        process.env.TZ = "UTC"
+        expect(outputs.size).toBe(1)
+        expect([...outputs][0]).toBe("13 octobre 2026")
+    })
+
+    it("formats a regular date", () => {
+        process.env.TZ = "Europe/Paris"
+        expect(formatDate(Date.UTC(2026, 8, 5, 12, 0), "fr")).toBe("5 septembre 2026")
+        process.env.TZ = "UTC"
+    })
+})
+
+describe("formatNumber", () => {
+    it("groups thousands deterministically per language", () => {
+        expect(formatNumber("fr", 1234567)).toBe("1\u202F234\u202F567")
+        expect(formatNumber("en", 1234567)).toBe("1,234,567")
+        expect(formatNumber("fr", 0)).toBe("0")
+    })
+})
diff --git a/frontend/app/core/lib/utils.ts b/frontend/app/core/lib/utils.ts
index 29f57df..b9dcdcc 100644
--- a/frontend/app/core/lib/utils.ts
+++ b/frontend/app/core/lib/utils.ts
@@ -68,13 +68,18 @@ export function formatNumber(language: string | undefined | null, value: number)
  * navigateur (noms de mois, ordre) et peut casser l'hydratation (#418).
  * Les noms de mois et le gabarit de format viennent des fichiers de
  * traduction (common.months / common.dateFormat).
+ *
+ * La date est lue en UTC : `getDate()`/`getMonth()` utilisent le fuseau local,
+ * qui diffère entre le serveur SSR (UTC) et le navigateur (ex. Europe/Paris),
+ * ce qui faisait diverger le HTML SSR et le rendu client pour les timestamps
+ * proches de minuit (erreur d'hydratation #418 sur la page serveur).
  */
 export function formatDate(timestamp: number, language: string | undefined | null): string {
     const lang = acceptableLanguage(language)
     const d = new Date(timestamp)
-    const day = d.getDate()
-    const year = d.getFullYear()
-    const month = translate(lang, `common.months.${d.getMonth()}`)
+    const day = d.getUTCDate()
+    const year = d.getUTCFullYear()
+    const month = translate(lang, `common.months.${d.getUTCMonth()}`)
     const template = translate(lang, "common.dateFormat")
     return template
         .replaceAll("{{day}}", String(day))
diff --git a/frontend/app/pages/account/index.tsx b/frontend/app/pages/account/index.tsx
index e3c945c..6332171 100644
--- a/frontend/app/pages/account/index.tsx
+++ b/frontend/app/pages/account/index.tsx
@@ -9,6 +9,7 @@ import type { MetaFunction } from "react-router"
 
 import { useWebPush } from "@/core/hooks/useWebPush"
 import { useToast } from "@/core/hooks/useToast"
+import { useInvalidateServers } from "@/core/hooks/useInvalidateServers"
 import { AccountServersTab } from "./components/AccountServersTab"
 import { AccountAlertsTab } from "./components/AccountAlertsTab"
 import { AccountProfileTab } from "./components/AccountProfileTab"
@@ -46,6 +47,7 @@ export default function Account() {
     const [servers, setServers] = useState<Server[]>([])
     const [allAlerts, setAllAlerts] = useState<ExtendedAlert[]>([])
     const [loading, setLoading] = useState(true)
+    const invalidateServers = useInvalidateServers()
 
     // Web Push State from Custom Hook
     const { 
@@ -88,6 +90,13 @@ export default function Account() {
         }
     }, [getToken, isLoaded, isSignedIn])
 
+    // Après un renommage : on recharge "mes serveurs" ET on invalide le cache
+    // global pour que la home et le Ctrl+K affichent le nouveau nom.
+    const handleServersMutated = useCallback(() => {
+        loadData()
+        invalidateServers()
+    }, [loadData, invalidateServers])
+
     useEffect(() => {
         if (isLoaded) {
             // eslint-disable-next-line react-hooks/set-state-in-effect
@@ -216,7 +225,7 @@ export default function Account() {
                             t={t} 
                             loading={loading} 
                             servers={servers} 
-                            loadData={loadData} 
+                            loadData={handleServersMutated} 
                         />
                     )}
 
diff --git a/frontend/app/pages/admin/index.tsx b/frontend/app/pages/admin/index.tsx
index 4684e2d..f49da6d 100644
--- a/frontend/app/pages/admin/index.tsx
+++ b/frontend/app/pages/admin/index.tsx
@@ -5,6 +5,7 @@ import { useAuth } from "@clerk/react"
 import { useLanguage } from "@/core/contexts/LanguageContext"
 import { useAdmin } from "@/core/contexts/AdminContext"
 import { useToast } from "@/core/hooks/useToast"
+import { useInvalidateServers } from "@/core/hooks/useInvalidateServers"
 import { fetchAdminUsers, fetchServers, toggleServerVisibility } from "@/core/lib/api"
 import type { User, Server } from "@/core/lib/api"
 import { Button } from "@/ui/components/button"
@@ -80,6 +81,7 @@ export default function AdminDashboard() {
     const [togglingServerId, setTogglingServerId] = useState<number | null>(null)
 
     const { showToast: triggerToast } = useToast()
+    const invalidateServers = useInvalidateServers()
 
     const loadData = useCallback(async () => {
         if (!isAdmin) return
@@ -104,6 +106,14 @@ export default function AdminDashboard() {
         }
     }, [isAdmin, getToken, t, triggerToast])
 
+    // Après une mutation (delete/rename/IP/favicon/visibilité) : on recharge le
+    // tableau admin ET on invalide le cache global pour que la home et le
+    // Ctrl+K reflètent le changement sans attendre l'expiration du staleTime.
+    const refreshAfterMutation = useCallback(() => {
+        loadData()
+        invalidateServers()
+    }, [loadData, invalidateServers])
+
     useEffect(() => {
         if (isLoaded && isAdmin) {
             // eslint-disable-next-line react-hooks/set-state-in-effect
@@ -124,6 +134,7 @@ export default function AdminDashboard() {
 
             if (result.success) {
                 setServers(prev => prev.map(s => s.id === serverId ? { ...s, hidden: !currentHidden } : s))
+                invalidateServers()
                 triggerToast("success", t("admin.toast.visibilitySuccess", { name: serverName }))
             } else {
                 triggerToast("error", result.message_key ? t(result.message_key) : result.message || t("common.error"))
@@ -345,7 +356,7 @@ export default function AdminDashboard() {
                             handleToggleServer={handleToggleServer}
                             getUserDisplayName={getUserDisplayName}
                             t={t}
-                            onRefresh={loadData}
+                            onRefresh={refreshAfterMutation}
                             triggerToast={triggerToast}
                         />
                     )}
diff --git a/frontend/app/pages/home/components/Hero3D.tsx b/frontend/app/pages/home/components/Hero3D.tsx
index 0d6e279..38d33eb 100644
--- a/frontend/app/pages/home/components/Hero3D.tsx
+++ b/frontend/app/pages/home/components/Hero3D.tsx
@@ -3,6 +3,7 @@ import { ArrowDown } from "lucide-react"
 import { useLanguage } from "@/core/contexts/LanguageContext"
 import { useTheme } from "@/core/hooks/useTheme"
 import type { Server as ServerType } from "@/core/lib/api"
+import { formatNumber } from "@/core/lib/utils"
 import { resolveToken, withAlpha } from "@/core/lib/theme-colors"
 
 // Predefined heights for the graph nodes (representing server player count stats)
@@ -24,19 +25,26 @@ const points = defaultYValues.map((y, idx) => {
     }
 })
 
-// Animated counter hook (module-level to comply with React rules of hooks)
+// Animated counter hook (module-level to comply with React rules of hooks).
+// SSR-safe : le compteur démarre toujours à 0 (comme le HTML serveur) et la
+// préférence `prefers-reduced-motion` n'est lue que dans l'effet, sinon le
+// premier rendu client diverge du SSR -> erreur d'hydratation #418.
 function useAnimatedCount(target: number, duration = 1200) {
-    const [prefersReducedMotion] = useState(
-        () => typeof window !== "undefined" && window.matchMedia("(prefers-reduced-motion: reduce)").matches,
-    )
     const [prevTarget, setPrevTarget] = useState(target)
-    const [count, setCount] = useState(() => (prefersReducedMotion ? target : 0))
+    const [count, setCount] = useState(0)
     if (prevTarget !== target) {
         setPrevTarget(target)
-        setCount(prefersReducedMotion ? target : 0)
+        setCount(0)
     }
     useEffect(() => {
-        if (prefersReducedMotion || target === 0) return
+        if (typeof window !== "undefined" && window.matchMedia("(prefers-reduced-motion: reduce)").matches) {
+            // Synchro au montage (pas de rendu serveur divergent : SSR et
+            // premier rendu client partent de 0).
+            // eslint-disable-next-line react-hooks/set-state-in-effect
+            setCount(target)
+            return
+        }
+        if (target === 0) return
         let start = 0
         const step = target / (duration / 16)
         const timer = setInterval(() => {
@@ -49,12 +57,12 @@ function useAnimatedCount(target: number, duration = 1200) {
             }
         }, 16)
         return () => clearInterval(timer)
-    }, [target, duration, prefersReducedMotion])
+    }, [target, duration])
     return count
 }
 
 export function Hero3D({ servers = [] }: { servers?: ServerType[] }) {
-    const { t } = useLanguage()
+    const { t, language } = useLanguage()
     const { theme } = useTheme()
     const canvasRef = useRef<HTMLCanvasElement | null>(null)
     const containerRef = useRef<HTMLDivElement | null>(null)
@@ -429,7 +437,7 @@ export function Hero3D({ servers = [] }: { servers?: ServerType[] }) {
                         <div className="flex items-center justify-center lg:justify-start gap-5 sm:gap-8">
                             <div className="flex flex-col items-center">
                                 <p className="text-2xl sm:text-3xl font-extrabold text-foreground tabular-nums flex items-baseline">
-                                    {animatedTotal.toLocaleString()}<span className="text-info text-xl sm:text-2xl font-extrabold">+</span>
+                                    {formatNumber(language, animatedTotal)}<span className="text-info text-xl sm:text-2xl font-extrabold">+</span>
                                 </p>
                                 <p className="text-xs sm:text-xs text-muted-foreground mt-0.5 font-medium">
                                     {t("hero.stats.servers")}
@@ -440,7 +448,7 @@ export function Hero3D({ servers = [] }: { servers?: ServerType[] }) {
                             
                             <div className="flex flex-col items-center">
                                 <p className="text-2xl sm:text-3xl font-extrabold text-foreground tabular-nums">
-                                    {animatedOnline.toLocaleString()}
+                                    {formatNumber(language, animatedOnline)}
                                 </p>
                                 <p className="text-xs sm:text-xs text-muted-foreground mt-0.5 font-medium">
                                     {t("hero.stats.online")}
@@ -451,7 +459,7 @@ export function Hero3D({ servers = [] }: { servers?: ServerType[] }) {
                             
                             <div className="flex flex-col items-center">
                                 <p className="text-2xl sm:text-3xl font-extrabold text-foreground tabular-nums">
-                                    {animatedPlayers.toLocaleString()}
+                                    {formatNumber(language, animatedPlayers)}
                                 </p>
                                 <p className="text-xs sm:text-xs text-muted-foreground mt-0.5 font-medium">
                                     {t("hero.stats.players")}
diff --git a/frontend/app/pages/home/index.tsx b/frontend/app/pages/home/index.tsx
index 9b2310e..4972fc5 100644
--- a/frontend/app/pages/home/index.tsx
+++ b/frontend/app/pages/home/index.tsx
@@ -15,6 +15,7 @@ import { useAuth } from "@clerk/react"
 import { useAdmin } from "@/core/contexts/AdminContext"
 import { useSearch } from "@/core/hooks/useSearch"
 import { useLanguage } from "@/core/contexts/LanguageContext"
+import { SERVERS_QUERY_KEY } from "@/core/lib/query-keys"
 
 import { Hero3D } from "@/pages/home/components/Hero3D"
 import { FaqSection } from "@/pages/home/components/FaqSection"
@@ -130,7 +131,7 @@ function ServerListContent({ initialServers }: { initialServers: Server[] }) {
     // données SSR. Remplace l'ancien doublon load()/handleRefresh(), les
     // caches module-level et le refetch manuel au montage.
     const { data: servers = initialServers || [], isPending, isFetching, error, refetch } = useQuery({
-        queryKey: ["servers"],
+        queryKey: SERVERS_QUERY_KEY,
         queryFn: async () => {
             const token = isLoaded && isSignedIn ? await getToken() : undefined
             return fetchServers(token ?? undefined, true)
diff --git a/frontend/app/ui/layout/SearchBar.tsx b/frontend/app/ui/layout/SearchBar.tsx
index 83ed87f..fd0dd9b 100644
--- a/frontend/app/ui/layout/SearchBar.tsx
+++ b/frontend/app/ui/layout/SearchBar.tsx
@@ -12,6 +12,7 @@ import { useNavigate } from "react-router"
 import { useQuery, useQueryClient } from "@tanstack/react-query"
 import { useLanguage } from "@/core/contexts/LanguageContext"
 import { useSearch } from "@/core/hooks/useSearch"
+import { SERVERS_QUERY_KEY, SERVERS_SEARCH_QUERY_KEY } from "@/core/lib/query-keys"
 import { MINUTE_MS } from "@/core/lib/time"
 
 import { LunarLogo } from "@/ui/components/LunarLogo"
@@ -57,11 +58,15 @@ export function SearchBar({ value: propValue, onChange: propOnChange, onSelect,
 
     const queryClient = useQueryClient()
     const { data: allServers = [] } = useQuery({
-        queryKey: ["servers-search", refreshCounter],
+        queryKey: [...SERVERS_SEARCH_QUERY_KEY, refreshCounter],
         queryFn: async () => {
             // Optimisation : Si la homepage a déjà chargé les serveurs (via SSR ou client), on les réutilise
-            const cachedServers = queryClient.getQueryData<Server[]>(["servers"])
-            if (cachedServers && cachedServers.length > 0) {
+            // SAUF si un refresh a été demandé (ajout de serveur) : le cache ["servers"]
+            // est alors invalidé et on doit refetcher pour que le nouveau serveur
+            // apparaisse dans le Ctrl+K.
+            const cachedServers = queryClient.getQueryData<Server[]>(SERVERS_QUERY_KEY)
+            const serversState = queryClient.getQueryState(SERVERS_QUERY_KEY)
+            if (cachedServers && cachedServers.length > 0 && !serversState?.isInvalidated) {
                 return cachedServers
             }
             
diff --git a/frontend/app/ui/layout/ThemeToggle.tsx b/frontend/app/ui/layout/ThemeToggle.tsx
index 338e5a5..2bf7b6d 100644
--- a/frontend/app/ui/layout/ThemeToggle.tsx
+++ b/frontend/app/ui/layout/ThemeToggle.tsx
@@ -8,7 +8,12 @@ export function ThemeToggle() {
     const { t } = useLanguage()
 
     return (
-        <Button variant="outline" size="icon" onClick={toggleTheme}>
+        // Sans cookie de thème, le SSR suppose "dark" alors que le client
+        // résout `prefers-color-scheme` : l'icône peut diverger au premier
+        // rendu (corrigée juste après par l'effet). Divergence attendue et
+        // bénigne, on coupe l'avertissement d'hydratation (même approche que
+        // `suppressHydrationWarning` sur <html> dans root.tsx).
+        <Button variant="outline" size="icon" onClick={toggleTheme} suppressHydrationWarning>
             {theme === "light" ? (
                 <Moon className="h-4 w-4" />
             ) : (