diff --git a/listener/src/config.ts b/listener/src/config.ts
index 67038d5..6c361e4 100644
--- a/listener/src/config.ts
+++ b/listener/src/config.ts
@@ -1,4 +1,4 @@
-import { Config, ContractConfig, DiscordConfig, WebhookSecret } from './types';
+import { Config, ContractConfig, DiscordConfig, WebhookSecret, AppCleanupConfig } from './types';
 
 export class ConfigError extends Error {
   constructor(message: string) {
@@ -112,6 +112,15 @@ function validateWebhookSecrets(value: unknown): WebhookSecret[] {
   });
 }
 
+function loadCleanupConfig(): AppCleanupConfig {
+  return {
+    intervalMs: parseIntegerEnv('CLEANUP_INTERVAL_MS', String(60 * 60 * 1000)),
+    notificationRetentionMs: parseIntegerEnv('NOTIFICATION_RETENTION_MS', String(7 * 24 * 60 * 60 * 1000)),
+    rateLimitEventRetentionMs: parseIntegerEnv('RATE_LIMIT_EVENT_RETENTION_MS', String(24 * 60 * 60 * 1000)),
+    eventRetentionMs: parseIntegerEnv('EVENT_RETENTION_MS', String(24 * 60 * 60 * 1000)),
+  };
+}
+
 export function loadConfig(): Config {
   const discord = loadDiscordConfig();
   const rawContractAddresses = parseJsonEnv<unknown>('CONTRACT_ADDRESSES', '[]');
@@ -152,6 +161,7 @@ export function loadConfig(): Config {
       maxRequests: parseIntegerEnv('RATE_LIMIT_MAX_REQUESTS', '60'),
       clientOverrides,
     },
+    cleanup: loadCleanupConfig(),
   };
 }
 
diff --git a/listener/src/index.ts b/listener/src/index.ts
index 1453e41..c6397cb 100644
--- a/listener/src/index.ts
+++ b/listener/src/index.ts
@@ -8,8 +8,10 @@ import { NotificationTemplateService } from './services/notification-template-se
 import { TemplateAuditTrail } from './services/template-audit-trail';
 import { getTemplateCache } from './services/notification-template-cache';
 import { NotificationAPI } from './services/notification-api';
+import { CleanupService } from './services/cleanup-service';
 import { initializeDatabase } from './database/database';
 import { DiscordNotificationService } from './services/discord-notification';
+import { eventRegistry } from './store/event-registry';
 import logger from './utils/logger';
 import { loadConfig, ConfigError } from './config';
 
@@ -22,11 +24,20 @@ async function main() {
   let scheduler: NotificationScheduler | null = null;
   let notificationAPI: NotificationAPI | null = null;
   let templateService: NotificationTemplateService | null = null;
+  let cleanupService: CleanupService | null = null;
 
   try {
     logger.info('Initializing database');
     const db = await initializeDatabase(config.databasePath);
 
+    // Rebuild registry with configured event TTL
+    if (config.cleanup) {
+      eventRegistry['ttlMs'] = config.cleanup.eventRetentionMs;
+    }
+
+    cleanupService = new CleanupService(db, eventRegistry, config.cleanup);
+    cleanupService.start();
+
     const templateRepository = new NotificationTemplateRepository(
       db,
       new TemplateAuditTrail(db),
@@ -71,6 +82,10 @@ async function main() {
   const shutdown = async () => {
     logger.info('Shutting down services...');
 
+    if (cleanupService) {
+      await cleanupService.stop();
+    }
+
     if (scheduler) {
       await scheduler.stop();
     }
diff --git a/listener/src/services/cleanup-service.test.ts b/listener/src/services/cleanup-service.test.ts
new file mode 100644
index 0000000..d320f90
--- /dev/null
+++ b/listener/src/services/cleanup-service.test.ts
@@ -0,0 +1,142 @@
+import { CleanupService } from './cleanup-service';
+import { EventRegistry } from '../store/event-registry';
+
+jest.mock('../utils/logger', () => ({
+  __esModule: true,
+  default: { debug: jest.fn(), info: jest.fn(), warn: jest.fn(), error: jest.fn() },
+}));
+
+// ── helpers ────────────────────────────────────────────────────────────────
+
+function makeDb(changes = 0) {
+  return {
+    run: jest.fn().mockResolvedValue({ lastID: 0, changes }),
+    get: jest.fn().mockResolvedValue({ count: changes }),
+  } as unknown as import('../database/database').Database;
+}
+
+function addEvent(registry: EventRegistry, overrides: Partial<{ receivedAt: number }> = {}) {
+  const event = registry.addFromInput({
+    eventId: `evt-${Math.random()}`,
+    contractAddress: 'CABC',
+    eventName: 'TestEvent',
+    ledger: 1,
+    type: 'contract',
+    topic: [],
+    value: { switch: () => ({ name: 'scvVoid' }), value: () => undefined } as any,
+  });
+  if (overrides.receivedAt !== undefined) {
+    (event as any).receivedAt = overrides.receivedAt;
+  }
+  return event;
+}
+
+// ── EventRegistry TTL tests ────────────────────────────────────────────────
+
+describe('EventRegistry TTL cleanup', () => {
+  it('pruneExpired removes events older than ttlMs', () => {
+    const registry = new EventRegistry(100, 1000);
+    addEvent(registry, { receivedAt: Date.now() - 2000 }); // expired
+    addEvent(registry, { receivedAt: Date.now() - 500 });  // fresh
+
+    const removed = registry.pruneExpired();
+
+    expect(removed).toBe(1);
+    expect(registry.count()).toBe(1);
+  });
+
+  it('pruneExpired keeps all events when none are expired', () => {
+    const registry = new EventRegistry(100, 10_000);
+    addEvent(registry);
+    addEvent(registry);
+
+    expect(registry.pruneExpired()).toBe(0);
+    expect(registry.count()).toBe(2);
+  });
+
+  it('startCleanup and stopCleanup control the interval', () => {
+    jest.useFakeTimers();
+    const registry = new EventRegistry(100, 500);
+    const spy = jest.spyOn(registry, 'pruneExpired');
+
+    registry.startCleanup(200);
+    jest.advanceTimersByTime(600);
+    expect(spy).toHaveBeenCalledTimes(3);
+
+    registry.stopCleanup();
+    jest.advanceTimersByTime(600);
+    expect(spy).toHaveBeenCalledTimes(3); // no more calls
+
+    jest.useRealTimers();
+  });
+});
+
+// ── CleanupService DB tests ────────────────────────────────────────────────
+
+describe('CleanupService', () => {
+  beforeEach(() => jest.useFakeTimers());
+  afterEach(() => jest.useRealTimers());
+
+  it('starts and fires db cleanup on interval', async () => {
+    const db = makeDb(3);
+    const registry = new EventRegistry();
+    const service = new CleanupService(db, registry, { intervalMs: 500, notificationRetentionMs: 1000, rateLimitEventRetentionMs: 1000 });
+
+    service.start();
+    jest.advanceTimersByTime(600);
+
+    // Allow pending promises to resolve
+    await Promise.resolve();
+
+    expect(db.run).toHaveBeenCalled();
+  });
+
+  it('runDbCleanup deletes old notifications and rate_limit_events', async () => {
+    const db = makeDb(5);
+    const registry = new EventRegistry();
+    const service = new CleanupService(db, registry, { intervalMs: 60000, notificationRetentionMs: 1000, rateLimitEventRetentionMs: 500 });
+
+    const result = await service.runDbCleanup();
+
+    // Two DELETE calls: scheduled_notifications + rate_limit_events
+    expect(db.run).toHaveBeenCalledTimes(2);
+    expect(db.run).toHaveBeenCalledWith(
+      expect.stringContaining('DELETE FROM scheduled_notifications'),
+      expect.any(Array),
+    );
+    expect(db.run).toHaveBeenCalledWith(
+      expect.stringContaining('DELETE FROM rate_limit_events'),
+      expect.any(Array),
+    );
+    expect(result.notifications).toBe(5);
+    expect(result.rateLimitEvents).toBe(5);
+  });
+
+  it('stop clears the interval and stops registry cleanup', async () => {
+    const db = makeDb();
+    const registry = new EventRegistry();
+    const stopRegistrySpy = jest.spyOn(registry, 'stopCleanup');
+    const service = new CleanupService(db, registry, { intervalMs: 200, notificationRetentionMs: 1000, rateLimitEventRetentionMs: 1000 });
+
+    service.start();
+    await service.stop();
+
+    jest.advanceTimersByTime(1000);
+    // db.run should not be called after stop (interval cleared)
+    expect(db.run).not.toHaveBeenCalled();
+    expect(stopRegistrySpy).toHaveBeenCalled();
+  });
+
+  it('calling start twice does not create duplicate intervals', () => {
+    const db = makeDb();
+    const registry = new EventRegistry();
+    const service = new CleanupService(db, registry, { intervalMs: 300, notificationRetentionMs: 1000, rateLimitEventRetentionMs: 1000 });
+
+    service.start();
+    service.start(); // second call is a no-op
+
+    jest.advanceTimersByTime(400);
+    // Should only fire once despite two start() calls
+    expect(db.run).toHaveBeenCalledTimes(2); // one interval tick × 2 SQL statements
+  });
+});
diff --git a/listener/src/services/cleanup-service.ts b/listener/src/services/cleanup-service.ts
new file mode 100644
index 0000000..16bbc3d
--- /dev/null
+++ b/listener/src/services/cleanup-service.ts
@@ -0,0 +1,79 @@
+import { Database } from '../database/database';
+import logger from '../utils/logger';
+import { EventRegistry } from '../store/event-registry';
+
+export interface CleanupConfig {
+  /** How often to run cleanup (ms). Default: 1 hour. */
+  intervalMs: number;
+  /** Retain completed/failed notifications for this long (ms). Default: 7 days. */
+  notificationRetentionMs: number;
+  /** Retain rate-limit audit events for this long (ms). Default: 24 hours. */
+  rateLimitEventRetentionMs: number;
+}
+
+const DEFAULTS: CleanupConfig = {
+  intervalMs: 60 * 60 * 1000,
+  notificationRetentionMs: 7 * 24 * 60 * 60 * 1000,
+  rateLimitEventRetentionMs: 24 * 60 * 60 * 1000,
+};
+
+export class CleanupService {
+  private timer: ReturnType<typeof setInterval> | null = null;
+  private readonly config: CleanupConfig;
+
+  constructor(
+    private readonly db: Database,
+    private readonly registry: EventRegistry,
+    config: Partial<CleanupConfig> = {},
+  ) {
+    this.config = { ...DEFAULTS, ...config };
+  }
+
+  start(): void {
+    if (this.timer) return;
+    this.registry.startCleanup(this.config.intervalMs);
+    this.timer = setInterval(() => void this.runDbCleanup(), this.config.intervalMs);
+    logger.info('CleanupService started', this.config as unknown as Record<string, unknown>);
+  }
+
+  async stop(): Promise<void> {
+    if (this.timer) {
+      clearInterval(this.timer);
+      this.timer = null;
+    }
+    this.registry.stopCleanup();
+    logger.info('CleanupService stopped');
+  }
+
+  async runDbCleanup(): Promise<{ notifications: number; executionLogs: number; rateLimitEvents: number }> {
+    const notificationCutoff = new Date(Date.now() - this.config.notificationRetentionMs).toISOString();
+    const rateLimitCutoff = new Date(Date.now() - this.config.rateLimitEventRetentionMs).toISOString();
+
+    const [notifResult, rateLimitResult] = await Promise.all([
+      this.db.run(
+        `DELETE FROM scheduled_notifications
+         WHERE status IN ('COMPLETED','FAILED','CANCELLED')
+           AND processing_completed_at < ?`,
+        [notificationCutoff],
+      ),
+      this.db.run(
+        `DELETE FROM rate_limit_events WHERE timestamp < ?`,
+        [rateLimitCutoff],
+      ),
+    ]);
+
+    // execution_log rows are cascade-deleted with their parent; count separately for metrics
+    const logResult = await this.db.get<{ count: number }>(
+      `SELECT changes() as count`,
+    );
+
+    const result = {
+      notifications: notifResult.changes,
+      executionLogs: 0, // removed via ON DELETE CASCADE
+      rateLimitEvents: rateLimitResult.changes,
+    };
+
+    logger.info('DB cleanup completed', result);
+    return result;
+  }
+}
diff --git a/listener/src/store/event-registry.ts b/listener/src/store/event-registry.ts
index a3b47c1..1595155 100644
--- a/listener/src/store/event-registry.ts
+++ b/listener/src/store/event-registry.ts
@@ -4,13 +4,40 @@ import { formatScValArray, formatScValValue } from '../utils/scval-format';
 import logger from '../utils/logger';
 
 const DEFAULT_MAX_EVENTS = 10000;
+const DEFAULT_TTL_MS = 24 * 60 * 60 * 1000; // 24 hours
 
 export class EventRegistry {
   private events: DisplayEvent[] = [];
   private readonly maxEvents: number;
+  private readonly ttlMs: number;
+  private cleanupTimer: ReturnType<typeof setInterval> | null = null;
 
-  constructor(maxEvents = DEFAULT_MAX_EVENTS) {
+  constructor(maxEvents = DEFAULT_MAX_EVENTS, ttlMs = DEFAULT_TTL_MS) {
     this.maxEvents = maxEvents;
+    this.ttlMs = ttlMs;
+  }
+
+  startCleanup(intervalMs = 60_000): void {
+    if (this.cleanupTimer) return;
+    this.cleanupTimer = setInterval(() => this.pruneExpired(), intervalMs);
+  }
+
+  stopCleanup(): void {
+    if (this.cleanupTimer) {
+      clearInterval(this.cleanupTimer);
+      this.cleanupTimer = null;
+    }
+  }
+
+  pruneExpired(): number {
+    const cutoff = Date.now() - this.ttlMs;
+    const before = this.events.length;
+    this.events = this.events.filter((e) => e.receivedAt >= cutoff);
+    const removed = before - this.events.length;
+    if (removed > 0) {
+      logger.info('Pruned expired events from registry', { removed, remaining: this.events.length });
+    }
+    return removed;
   }
 
   addFromInput(input: RegistryEventInput): DisplayEvent {
diff --git a/listener/src/types/index.ts b/listener/src/types/index.ts
index 2d10e7f..d9d29b6 100644
--- a/listener/src/types/index.ts
+++ b/listener/src/types/index.ts
@@ -45,6 +45,7 @@ export interface Config {
   scheduler?: SchedulerConfig;
   databasePath?: string;
   rateLimit?: RateLimitConfig;
+  cleanup?: AppCleanupConfig;
 }
 
 export interface SchedulerConfig {
@@ -56,3 +57,14 @@ export interface SchedulerConfig {
   timingBufferMs: number;
 }
 
+export interface AppCleanupConfig {
+  /** How often to run cleanup jobs (ms). */
+  intervalMs: number;
+  /** Retain completed/failed/cancelled notifications for this long (ms). */
+  notificationRetentionMs: number;
+  /** Retain rate-limit audit rows for this long (ms). */
+  rateLimitEventRetentionMs: number;
+  /** Retain in-memory events for this long (ms). */
+  eventRetentionMs: number;
+}
+