diff --git a/.beads/interactions.jsonl b/.beads/interactions.jsonl
index 65b2292..338f9cf 100644
--- a/.beads/interactions.jsonl
+++ b/.beads/interactions.jsonl
@@ -8,3 +8,5 @@
 {"id":"int-a4d53813","kind":"field_change","created_at":"2026-06-29T14:35:55.325922806Z","actor":"dawn","issue_id":"nucleus-bkx","extra":{"field":"status","new_value":"closed","old_value":"open","reason":"Epic complete: all list virtualizations rewritten to use TanStack Virtual."}}
 {"id":"int-3ef022dd","kind":"field_change","created_at":"2026-06-29T15:44:24.7334854Z","actor":"dawn","issue_id":"nucleus-huf","extra":{"field":"status","new_value":"closed","old_value":"in_progress","reason":"Converted global notificationStream, jetstream, and pulsingPostId stores to Svelte 5 state objects."}}
 {"id":"int-fb44cac5","kind":"field_change","created_at":"2026-06-29T16:02:53.45125394Z","actor":"dawn","issue_id":"nucleus-bwr","extra":{"field":"status","new_value":"closed","old_value":"in_progress","reason":"Fixed Svelte 5 Date and Set lint errors by using Date.parse, SvelteDate, and SvelteSet."}}
+{"id":"int-0e35bdb1","kind":"field_change","created_at":"2026-06-29T16:32:22.208395256Z","actor":"dawn","issue_id":"nucleus-20e","extra":{"field":"status","new_value":"closed","old_value":"in_progress","reason":"Implemented gcPosts function and background interval to prune unreferenced posts."}}
+{"id":"int-2be9147c","kind":"field_change","created_at":"2026-06-29T16:34:32.902566131Z","actor":"dawn","issue_id":"nucleus-cfv","extra":{"field":"status","new_value":"closed","old_value":"in_progress","reason":"Converted settings store to Svelte 5 state and updated all usages across components and pages."}}
diff --git a/.beads/issues.jsonl b/.beads/issues.jsonl
index 305eb09..6dde17f 100644
--- a/.beads/issues.jsonl
+++ b/.beads/issues.jsonl
@@ -1,3 +1,5 @@
+{"_type":"issue","id":"nucleus-20e","title":"Implement post cache garbage collection","description":"Add a gcPosts function to state.svelte.ts that runs periodically to prune orphaned post records from allPosts map and clean up secondary indexes.","status":"closed","priority":1,"issue_type":"task","assignee":"dawn","owner":"90008@klbr.net","created_at":"2026-06-29T16:31:45Z","created_by":"dawn","updated_at":"2026-06-29T16:32:22Z","started_at":"2026-06-29T16:31:54Z","closed_at":"2026-06-29T16:32:22Z","close_reason":"Implemented gcPosts function and background interval to prune unreferenced posts.","dependency_count":0,"dependent_count":0,"comment_count":0}
+{"_type":"issue","id":"nucleus-cfv","title":"Modernize settings store to Svelte 5 state","description":"Convert settings store in settings.ts to Svelte 5 state object, update imports and usage in BskyPost, FeedSelector, RichText, SettingsView, and +page.svelte.","status":"closed","priority":2,"issue_type":"task","assignee":"dawn","owner":"90008@klbr.net","created_at":"2026-06-29T16:32:01Z","created_by":"dawn","updated_at":"2026-06-29T16:34:33Z","started_at":"2026-06-29T16:32:09Z","closed_at":"2026-06-29T16:34:33Z","close_reason":"Converted settings store to Svelte 5 state and updated all usages across components and pages.","dependency_count":0,"dependent_count":0,"comment_count":0}
 {"_type":"issue","id":"nucleus-bwr","title":"Resolve Svelte 5 Date and Set lint errors in state.svelte.ts","description":"Replace built-in Date instantiation with Date.parse or SvelteDate, and built-in Set instantiation with SvelteSet to satisfy Svelte 5 lint rules.","status":"closed","priority":2,"issue_type":"task","assignee":"dawn","owner":"90008@klbr.net","created_at":"2026-06-29T16:01:47Z","created_by":"dawn","updated_at":"2026-06-29T16:02:53Z","started_at":"2026-06-29T16:01:55Z","closed_at":"2026-06-29T16:02:53Z","close_reason":"Fixed Svelte 5 Date and Set lint errors by using Date.parse, SvelteDate, and SvelteSet.","dependency_count":0,"dependent_count":0,"comment_count":0}
 {"_type":"issue","id":"nucleus-huf","title":"Modernize state stores to Svelte 5 Runes","description":"Convert notificationStream, jetstream, and pulsingPostId from Svelte 4 writables to Svelte 5 state/derived runes, updating components and routes.","status":"closed","priority":2,"issue_type":"task","assignee":"dawn","owner":"90008@klbr.net","created_at":"2026-06-29T15:41:52Z","created_by":"dawn","updated_at":"2026-06-29T15:44:25Z","started_at":"2026-06-29T15:42:02Z","closed_at":"2026-06-29T15:44:25Z","close_reason":"Converted global notificationStream, jetstream, and pulsingPostId stores to Svelte 5 state objects.","dependency_count":0,"dependent_count":0,"comment_count":0}
 {"_type":"issue","id":"nucleus-9ot","title":"Clean up @tutorlatin/svelte-tiny-virtual-list and verify build/lints","description":"Uninstall unused dependency, run linter and build to make sure everything works perfectly","status":"closed","priority":2,"issue_type":"task","assignee":"dawn","owner":"90008@klbr.net","created_at":"2026-06-29T14:27:01Z","created_by":"dawn","updated_at":"2026-06-29T14:35:48Z","started_at":"2026-06-29T14:33:32Z","closed_at":"2026-06-29T14:35:48Z","close_reason":"Removed old package and verified typescript / prettier formatting","dependencies":[{"issue_id":"nucleus-9ot","depends_on_id":"nucleus-3w3","type":"blocks","created_at":"2026-06-29T17:28:10Z","created_by":"dawn","metadata":"{}"},{"issue_id":"nucleus-9ot","depends_on_id":"nucleus-ehl","type":"blocks","created_at":"2026-06-29T17:28:23Z","created_by":"dawn","metadata":"{}"},{"issue_id":"nucleus-9ot","depends_on_id":"nucleus-fcu","type":"blocks","created_at":"2026-06-29T17:28:15Z","created_by":"dawn","metadata":"{}"},{"issue_id":"nucleus-9ot","depends_on_id":"nucleus-ib8","type":"blocks","created_at":"2026-06-29T17:28:19Z","created_by":"dawn","metadata":"{}"},{"issue_id":"nucleus-9ot","depends_on_id":"nucleus-n16","type":"blocks","created_at":"2026-06-29T17:28:02Z","created_by":"dawn","metadata":"{}"},{"issue_id":"nucleus-9ot","depends_on_id":"nucleus-xnz","type":"blocks","created_at":"2026-06-29T17:28:06Z","created_by":"dawn","metadata":"{}"}],"dependency_count":6,"dependent_count":1,"comment_count":0}
diff --git a/src/components/BskyPost.svelte b/src/components/BskyPost.svelte
index 84cf38c..f1ff6d2 100644
--- a/src/components/BskyPost.svelte
+++ b/src/components/BskyPost.svelte
@@ -454,7 +454,9 @@
 			placement="bottom-end"
 		>
 			{@render dropdownItem('heroicons:link-20-solid', 'copy link to post', () =>
-				navigator.clipboard.writeText(`${$settings.socialAppUrl}/profile/${did}/post/${rkey}`)
+				navigator.clipboard.writeText(
+					`${settings.current.socialAppUrl}/profile/${did}/post/${rkey}`
+				)
 			)}
 			{@render dropdownItem(undefined, 'copy at uri', () =>
 				navigator.clipboard.writeText(post.uri)
diff --git a/src/components/FeedSelector.svelte b/src/components/FeedSelector.svelte
index 6356d39..ef3d330 100644
--- a/src/components/FeedSelector.svelte
+++ b/src/components/FeedSelector.svelte
@@ -14,7 +14,7 @@
 
 	let isOpen = $state(false);
 
-	const savedFeeds = $derived($settings.feeds);
+	const savedFeeds = $derived(settings.current.feeds);
 	const sortedFeeds = $derived(
 		[...savedFeeds].sort((a, b) => (b.pinned ? 1 : 0) - (a.pinned ? 1 : 0))
 	);
diff --git a/src/components/RichText.svelte b/src/components/RichText.svelte
index 1e79a63..65bcacb 100644
--- a/src/components/RichText.svelte
+++ b/src/components/RichText.svelte
@@ -58,7 +58,7 @@
 				{:else if feature.$type === 'app.bsky.richtext.facet#tag'}
 					<a
 						class="text-(--nucleus-accent2)"
-						href={`${$settings.socialAppUrl}/search?q=${encodeURIComponent('#' + feature.tag)}`}
+						href={`${settings.current.socialAppUrl}/search?q=${encodeURIComponent('#' + feature.tag)}`}
 						target="_blank"
 						rel="noopener noreferrer">{@render plainText(text)}</a
 					>
diff --git a/src/components/SettingsView.svelte b/src/components/SettingsView.svelte
index d00d613..42faf04 100644
--- a/src/components/SettingsView.svelte
+++ b/src/components/SettingsView.svelte
@@ -1,6 +1,6 @@
 <script lang="ts">
 	import { needsReload, settings } from '$lib/settings';
-	import { get } from 'svelte/store';
+
 	import Tabs from './Tabs.svelte';
 	import { portal } from 'svelte-portal';
 	import {
@@ -29,11 +29,11 @@
 
 	let { tab }: Props = $props();
 
-	let localSettings = $state(get(settings));
-	let hasReloadChanges = $derived(needsReload($settings, localSettings));
+	let localSettings = $state($state.snapshot(settings.current));
+	let hasReloadChanges = $derived(needsReload(settings.current, localSettings));
 
 	$effect(() => {
-		$settings.theme = localSettings.theme;
+		settings.current = { ...settings.current, theme: localSettings.theme };
 	});
 
 	const handleSave = () => {
diff --git a/src/lib/at/index.ts b/src/lib/at/index.ts
index fa73615..d448eaf 100644
--- a/src/lib/at/index.ts
+++ b/src/lib/at/index.ts
@@ -1,11 +1,10 @@
 import { settings } from '$lib/settings';
 import type { Did } from '@atcute/lexicons';
-import { get } from 'svelte/store';
 
-export const slingshotUrl: URL = new URL(get(settings).endpoints.slingshot);
-export const spacedustUrl: URL = new URL(get(settings).endpoints.spacedust);
-export const constellationUrl: URL = new URL(get(settings).endpoints.constellation);
-export const pocketUrl: URL = new URL(get(settings).endpoints.pocket);
-export const cdnUrl: URL = new URL(get(settings).endpoints.cdn);
+export const slingshotUrl: URL = new URL(settings.current.endpoints.slingshot);
+export const spacedustUrl: URL = new URL(settings.current.endpoints.spacedust);
+export const constellationUrl: URL = new URL(settings.current.endpoints.constellation);
+export const pocketUrl: URL = new URL(settings.current.endpoints.pocket);
+export const cdnUrl: URL = new URL(settings.current.endpoints.cdn);
 
 export const httpToDidWeb = (url: string): Did => `did:web:${new URL(url).hostname}`;
diff --git a/src/lib/settings.ts b/src/lib/settings.ts
index 9a0f8cb..d44b939 100644
--- a/src/lib/settings.ts
+++ b/src/lib/settings.ts
@@ -1,4 +1,3 @@
-import { writable } from 'svelte/store';
 import { defaultTheme, type Theme } from './theme';
 import type { FeedGenerator } from './at/feeds';
 
@@ -37,60 +36,71 @@ export const defaultSettings: Settings = {
 	feeds: []
 };
 
-const createSettingsStore = () => {
-	// Prevent SSR crash if localStorage is missing
-	const stored = typeof localStorage !== 'undefined' ? localStorage.getItem('settings') : null;
+const applyThemeToDocument = (theme: Theme) => {
+	if (typeof document === 'undefined') return;
+	document.documentElement.style.setProperty('--nucleus-bg', theme.bg);
+	document.documentElement.style.setProperty('--nucleus-fg', theme.fg);
+	document.documentElement.style.setProperty('--nucleus-accent', theme.accent);
+	document.documentElement.style.setProperty('--nucleus-accent2', theme.accent2);
 
-	const initial: Partial<Settings> = stored ? JSON.parse(stored) : defaultSettings;
-	initial.endpoints = { ...defaultSettings.endpoints, ...initial.endpoints };
-	initial.theme = { ...defaultSettings.theme, ...initial.theme };
-	initial.socialAppUrl = initial.socialAppUrl ?? defaultSettings.socialAppUrl;
-	initial.feeds = initial.feeds ?? defaultSettings.feeds;
+	const oldMeta = document.querySelector('meta[name="theme-color"]');
+	if (oldMeta) oldMeta.remove();
 
-	const { subscribe, set, update } = writable<Settings>(initial as Settings);
+	const metaThemeColor = document.createElement('meta');
+	metaThemeColor.setAttribute('name', 'theme-color');
+	metaThemeColor.setAttribute('content', theme.bg);
+	document.head.appendChild(metaThemeColor);
+};
 
-	subscribe((settings) => {
-		if (typeof document === 'undefined') return;
-		const theme = settings.theme;
-		document.documentElement.style.setProperty('--nucleus-bg', theme.bg);
-		document.documentElement.style.setProperty('--nucleus-fg', theme.fg);
-		document.documentElement.style.setProperty('--nucleus-accent', theme.accent);
-		document.documentElement.style.setProperty('--nucleus-accent2', theme.accent2);
+// Private reactive state
+let _settings = $state<Settings>(defaultSettings);
 
-		const oldMeta = document.querySelector('meta[name="theme-color"]');
-		if (oldMeta) oldMeta.remove();
+if (typeof localStorage !== 'undefined') {
+	const stored = localStorage.getItem('settings');
+	if (stored) {
+		try {
+			const parsed = JSON.parse(stored);
+			_settings = {
+				endpoints: { ...defaultSettings.endpoints, ...parsed.endpoints },
+				theme: { ...defaultSettings.theme, ...parsed.theme },
+				socialAppUrl: parsed.socialAppUrl ?? defaultSettings.socialAppUrl,
+				feeds: parsed.feeds ?? defaultSettings.feeds
+			};
+		} catch (e) {
+			console.error('Failed to parse settings from localStorage', e);
+		}
+	}
+}
 
-		const metaThemeColor = document.createElement('meta');
-		metaThemeColor.setAttribute('name', 'theme-color');
-		metaThemeColor.setAttribute('content', theme.bg);
-		document.head.appendChild(metaThemeColor);
-	});
+// Apply theme initially if in browser
+if (typeof document !== 'undefined') {
+	applyThemeToDocument(_settings.theme);
+}
 
-	return {
-		subscribe,
-		set: (value: Settings) => {
-			if (typeof localStorage !== 'undefined')
-				localStorage.setItem('settings', JSON.stringify(value));
-			set(value);
-		},
-		update: (fn: (value: Settings) => Settings) => {
-			update((value) => {
-				const newValue = fn(value);
-				if (typeof localStorage !== 'undefined')
-					localStorage.setItem('settings', JSON.stringify(newValue));
-				return newValue;
-			});
-		},
-		reset: () => {
-			if (typeof localStorage !== 'undefined')
-				localStorage.setItem('settings', JSON.stringify(defaultSettings));
-			set(defaultSettings);
+export const settings = {
+	get current() {
+		return _settings;
+	},
+	set current(value: Settings) {
+		_settings = value;
+		if (typeof localStorage !== 'undefined') {
+			localStorage.setItem('settings', JSON.stringify(value));
 		}
-	};
+		applyThemeToDocument(value.theme);
+	},
+	// Compatibility wrapper for settings.set
+	set(value: Settings) {
+		this.current = value;
+	},
+	// Compatibility wrapper for settings.update
+	update(fn: (value: Settings) => Settings) {
+		this.current = fn(this.current);
+	},
+	reset() {
+		this.current = defaultSettings;
+	}
 };
 
-export const settings = createSettingsStore();
-
 export const needsReload = (current: Settings, other: Settings): boolean => {
 	return (
 		current.endpoints.slingshot !== other.endpoints.slingshot ||
diff --git a/src/lib/state.svelte.ts b/src/lib/state.svelte.ts
index fa2a03f..deada44 100644
--- a/src/lib/state.svelte.ts
+++ b/src/lib/state.svelte.ts
@@ -1115,11 +1115,86 @@ export const handleNotification = async (event: NotificationsStreamEvent) => {
 	}
 };
 
+export const gcPosts = () => {
+	const activeUris = new SvelteSet<ResourceUri>();
+
+	// 1. Collect all URIs from timelines
+	for (const timeline of timelines.values()) {
+		for (const uri of timeline) {
+			activeUris.add(uri);
+		}
+	}
+
+	// 2. Collect all URIs from feedTimelines
+	for (const feedMap of feedTimelines.values()) {
+		for (const feedUris of feedMap.values()) {
+			for (const uri of feedUris) {
+				activeUris.add(uri);
+			}
+		}
+	}
+
+	// 3. Collect all URIs from followingFeed
+	for (const feed of followingFeed.values()) {
+		for (const uri of feed) {
+			activeUris.add(uri);
+		}
+	}
+
+	// 4. Collect all URIs from followingBuffer
+	for (const buffer of followingBuffer.values()) {
+		for (const uri of buffer) {
+			activeUris.add(uri);
+		}
+	}
+
+	// 5. Clean up allPosts
+	let prunedCount = 0;
+	for (const uri of allPosts.keys()) {
+		if (!activeUris.has(uri)) {
+			allPosts.delete(uri);
+			prunedCount++;
+
+			// remove from other index maps
+			postsByDid.forEach((set) => set.delete(uri));
+			postsByRootUri.forEach((set) => set.delete(uri));
+			replyIndex.forEach((set) => set.delete(uri));
+			deletedPosts.delete(uri);
+		}
+	}
+
+	// 6. Clean up empty sets/maps in index maps to prevent memory leak
+	for (const [did, set] of postsByDid) {
+		if (set.size === 0) postsByDid.delete(did);
+	}
+	for (const [rootUri, set] of postsByRootUri) {
+		if (set.size === 0) postsByRootUri.delete(rootUri);
+	}
+	for (const [did, set] of replyIndex) {
+		if (set.size === 0) replyIndex.delete(did);
+	}
+
+	if (prunedCount > 0) {
+		console.log(
+			`[GC] Pruned ${prunedCount} unused posts from cache. Active posts: ${allPosts.size}`
+		);
+	}
+};
+
 export const currentTime = new SvelteDate();
 
-if (typeof window !== 'undefined')
+if (typeof window !== 'undefined') {
 	setInterval(() => {
 		currentTime.setTime(Date.now());
 	}, 1000);
 
+	// Run post cache garbage collection every 3 minutes
+	setInterval(
+		() => {
+			gcPosts();
+		},
+		1000 * 60 * 3
+	);
+}
+
 export const router = new Router();
diff --git a/src/routes/[...catchall]/+page.svelte b/src/routes/[...catchall]/+page.svelte
index db05eee..cc53126 100644
--- a/src/routes/[...catchall]/+page.svelte
+++ b/src/routes/[...catchall]/+page.svelte
@@ -125,9 +125,9 @@
 			);
 		});
 
-		console.log(`creating jetstream subscription to ${$settings.endpoints.jetstream}`);
+		console.log(`creating jetstream subscription to ${settings.current.endpoints.jetstream}`);
 		const jetstreamSub = new JetstreamSubscription({
-			url: $settings.endpoints.jetstream,
+			url: settings.current.endpoints.jetstream,
 			wantedCollections: ['app.bsky.feed.post'],
 			// this is here because if wantedDids is zero jetstream will send all events
 			wantedDids: ['did:web:guestbook.gaze.systems']