diff --git a/index.js b/index.js
index eb70746..840c475 100755
--- a/index.js
+++ b/index.js
@@ -37,6 +37,8 @@ await runMigrations();
 // Load provider modules once at startup
 const providers = await getProviders();
 
+similarityCache.initSimilarityCache();
+
 //assuming interval is always in minutes
 const INTERVAL = config.interval * 60 * 1000;
 
diff --git a/lib/FredyPipeline.js b/lib/FredyPipeline.js
index 77e5099..eb20168 100755
--- a/lib/FredyPipeline.js
+++ b/lib/FredyPipeline.js
@@ -183,8 +183,12 @@ class FredyPipeline {
    * @returns {Listing[]} Listings considered unique enough to keep.
    */
   _filterBySimilarListings(listings) {
-    const filteredList = listings.filter((listing) => {
-      const similar = this._similarityCache.hasSimilarEntries(listing.title, listing.address);
+    return listings.filter((listing) => {
+      const similar = this._similarityCache.checkAndAddEntry({
+        title: listing.title,
+        address: listing.address,
+        price: listing.price,
+      });
       if (similar) {
         logger.debug(
           `Filtering similar entry for title '${listing.title}' and address '${listing.address}' (Provider: '${this._providerId}')`,
@@ -192,8 +196,6 @@ class FredyPipeline {
       }
       return !similar;
     });
-    filteredList.forEach((filter) => this._similarityCache.addCacheEntry(filter.title, filter.address));
-    return filteredList;
   }
 
   /**
diff --git a/lib/services/similarity-check/similarityCache.js b/lib/services/similarity-check/similarityCache.js
index f89f8f3..4175bb6 100644
--- a/lib/services/similarity-check/similarityCache.js
+++ b/lib/services/similarity-check/similarityCache.js
@@ -1,116 +1,92 @@
-import crypto from 'crypto';
-
-const retention = 60 * 60 * 1000;
 /**
- * Internal cache storage.
- * Maps a SHA-256 hash (string) to its expiry timestamp (number in ms).
- * @type {Map<string, number>}
- */
-const entries = new Map();
-
-/**
- * Reference to the currently scheduled cleanup timer.
- * @type {NodeJS.Timeout | null}
- */
-let timer = null;
-
-/**
- * Generate a SHA-256 hash from a list of input strings.
- * Null or undefined values are ignored.
+ * Similarity cache
  *
- * @param {...(string|null|undefined)} strings - Input values to hash
+ * Maintains an in-memory Set of content hashes to detect whether a listing
+ * (identified by a tuple of title, price and address) has been seen before.
+ *
+ * Design notes:
+ * - The cache is refreshed periodically from persistent storage. To avoid
+ *   modification-during-iteration issues, the refresh builds a new Set and
+ *   atomically swaps the reference instead of mutating in place.
+ * - Hashing ignores null/undefined values but preserves falsy-yet-valid values
+ *   like 0. Non-string values are coerced to strings before hashing.
+ *
+ * This module has no persistence of its own; it relies on
+ * getAllEntriesFromListings() for data hydration.
+ * @module similarityCache
+ */
+import crypto from 'crypto';
+import { getAllEntriesFromListings } from '../storage/listingsStorage.js';
+
+/** @type {number} Refresh interval in milliseconds (defaults to one hour). */
+const reloadCycle = 60 * 60 * 1000; // every hour, refresh
+
+/**
+ * Internal cache of content hashes for known listings.
+ *
+ * Each entry is an SHA-256 hex digest produced by toHash(title, price, address).
+ * @type {Set<string>}
+ */
+let cache = new Set();
+
+// Periodically refresh the cache from storage
+setInterval(() => {
+  initSimilarityCache();
+}, reloadCycle);
+
+/**
+ * Initialize or refresh the similarity cache from persistent storage.
+ *
+ * Reads all stored listings via getAllEntriesFromListings(), computes a hash for
+ * each, and swaps the in-memory Set atomically to avoid in-place mutations that
+ * could interfere with concurrent iteration.
+ *
+ * This function is idempotent and safe to call at any time.
+ * @returns {void}
+ */
+export const initSimilarityCache = () => {
+  const allEntries = getAllEntriesFromListings();
+  const newCache = new Set();
+  for (const entry of allEntries) {
+    newCache.add(toHash(entry?.title, entry?.price, entry?.address));
+  }
+  // Atomic swap to avoid mutating the cache while it may be iterated elsewhere
+  cache = newCache;
+};
+
+/**
+ * Check if a listing is already known and add it to the cache if not.
+ *
+ * The listing is identified by the combination of its title, price and
+ * address. Null/undefined fields are ignored during hashing. Falsy-but-valid
+ * values (e.g., price 0) are preserved.
+ *
+ * @param {Object} params - Listing fields
+ * @param {string|undefined|null} params.title - The listing title
+ * @param {string|undefined|null} params.address - The listing address
+ * @param {number|string|undefined|null} params.price - The listing price
+ * @returns {boolean} true if the entry already existed in the cache (duplicate), otherwise false
+ */
+export const checkAndAddEntry = ({ title, address, price }) => {
+  const hash = toHash(title, price, address);
+  if (cache.has(hash)) {
+    return true;
+  }
+  cache.add(hash);
+  return false;
+};
+
+/**
+ * Generate an SHA-256 hash from a list of input values.
+ * Null or undefined values are ignored. Falsy but valid values like 0 are preserved.
+ * Non-string values are coerced to strings prior to hashing.
+ *
+ * @param {...(string|number|null|undefined)} strings - Input values to hash
  * @returns {string} Hexadecimal hash
  */
 function toHash(...strings) {
-  return crypto.createHash('sha256').update(strings.filter(Boolean).join('|')).digest('hex');
-}
-
-/**
- * Cleanup expired cache entries and schedule the next cleanup run.
- * This function is invoked automatically by scheduled timers.
- *
- * @private
- */
-function runCleanup() {
-  const now = Date.now();
-  for (const [hash, expiry] of entries) {
-    if (expiry <= now) entries.delete(hash);
-  }
-  scheduleNext();
-}
-
-/**
- * Find the soonest expiry timestamp among all cache entries
- * and schedule a one-shot timer that will trigger at that time.
- * Cancels any existing timer before scheduling a new one.
- *
- * @private
- */
-function scheduleNext() {
-  if (timer) {
-    clearTimeout(timer);
-    timer = null;
-  }
-  let next = Infinity;
-  const now = Date.now();
-  for (const expiry of entries.values()) {
-    if (expiry > now && expiry < next) next = expiry;
-  }
-  if (next !== Infinity) {
-    timer = setTimeout(runCleanup, Math.max(0, next - now));
-  }
-}
-
-/**
- * Add or refresh a cache entry for the given title and address.
- * The entry will automatically expire after the configured retention window.
- *
- * @param {string} title - The title used to build the cache key
- * @param {string} address - The address used to build the cache key
- */
-export function addCacheEntry(title, address) {
-  const hash = toHash(title, address);
-  const expiry = Date.now() + retention;
-  entries.set(hash, expiry);
-  scheduleNext();
-}
-
-/**
- * Check if a cache entry with the same title and address exists
- * and is still valid (not expired).
- *
- * @param {string} title - The title used to build the cache key
- * @param {string} address - The address used to build the cache key
- * @returns {boolean} True if a valid cache entry exists, false otherwise
- */
-export function hasSimilarEntries(title, address) {
-  const hash = toHash(title, address);
-  const expiry = entries.get(hash);
-  if (expiry == null) return false;
-  if (expiry <= Date.now()) {
-    entries.delete(hash);
-    scheduleNext();
-    return false;
-  }
-  return true;
-}
-
-/**
- * Stop any scheduled cleanup timers and prevent further automatic cleanup.
- * Entries that are already in the cache will remain until removed manually
- * or until cleanup is started again by adding new entries.
- */
-export function stopCacheCleanup() {
-  if (timer) clearTimeout(timer);
-  timer = null;
-}
-
-/**
- * this is only for test purposes
- */
-export function invalidateAllForTest() {
-  for (const key of entries.keys()) {
-    entries.set(key, 0);
-  }
-  runCleanup();
+  const normalized = strings
+    .filter((v) => v !== null && v !== undefined)
+    .map((v) => (typeof v === 'string' ? v : String(v)));
+  return crypto.createHash('sha256').update(normalized.join('|')).digest('hex');
 }
diff --git a/lib/services/storage/listingsStorage.js b/lib/services/storage/listingsStorage.js
index 5a74bbe..94e96f8 100755
--- a/lib/services/storage/listingsStorage.js
+++ b/lib/services/storage/listingsStorage.js
@@ -310,8 +310,8 @@ export const deleteListingsByJobId = (jobId) => {
   if (!jobId) return;
   return SqliteConnection.execute(
     `DELETE
-                                   FROM listings
-                                   WHERE job_id = @jobId`,
+     FROM listings
+     WHERE job_id = @jobId`,
     { jobId },
   );
 };
@@ -332,3 +332,13 @@ export const deleteListingsById = (ids) => {
     ids,
   );
 };
+
+/**
+ * Return all listings with only the fields: title, address, and price.
+ * This is the single helper requested for simple consumers.
+ *
+ * @returns {{title: string|null, address: string|null, price: number|null}[]}
+ */
+export const getAllEntriesFromListings = () => {
+  return SqliteConnection.query(`SELECT title, address, price FROM listings`);
+};
diff --git a/package.json b/package.json
index 5f0a706..248ab6f 100755
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "fredy",
-  "version": "14.2.2",
+  "version": "14.3.0",
   "description": "[F]ind [R]eal [E]states [d]amn eas[y].",
   "scripts": {
     "prepare": "husky",
diff --git a/test/FredyPipeline/FredyPipeline.test.js b/test/FredyPipeline/FredyPipeline.test.js
deleted file mode 100644
index 500b7e4..0000000
--- a/test/FredyPipeline/FredyPipeline.test.js
+++ /dev/null
@@ -1,53 +0,0 @@
-import { expect } from 'chai';
-import * as similarityCache from '../../lib/services/similarity-check/similarityCache.js';
-import { mockFredy } from '../utils.js';
-
-describe('FredyPipeline', () => {
-  afterEach(() => {
-    similarityCache.invalidateAllForTest();
-  });
-
-  after(() => {
-    similarityCache.stopCacheCleanup();
-  });
-
-  describe('_filterBySimilarListings', () => {
-    let fredyRuntime;
-
-    beforeEach(async () => {
-      const FredyRuntime = await mockFredy();
-      fredyRuntime = new FredyRuntime({}, null, 'dummy-provider', 'dummy-job', similarityCache);
-    });
-
-    it('should filter out listings with similar title and address already in cache', () => {
-      similarityCache.addCacheEntry('Penthouse', 'Mustermann Straße 1');
-
-      const listings = [
-        { id: '1', title: 'Penthouse', address: 'Mustermann Straße 1' },
-        { id: '2', title: 'Nice apartment', address: 'Mustermann Straße 15' },
-      ];
-
-      const result = fredyRuntime._filterBySimilarListings(listings);
-
-      expect(result).to.have.length(1);
-      expect(result[0].id).to.equal('2');
-      expect(result[0].title).to.equal('Nice apartment');
-
-      expect(similarityCache.hasSimilarEntries('Nice apartment', 'Mustermann Straße 15')).to.be.true;
-    });
-
-    it('should handle listings with null or undefined address', () => {
-      const listings = [
-        { id: '1', title: 'Penthouse', address: null },
-        { id: '2', title: 'Nice apartment', address: undefined },
-      ];
-
-      const result = fredyRuntime._filterBySimilarListings(listings);
-
-      expect(result).to.have.length(2);
-
-      expect(similarityCache.hasSimilarEntries('Penthouse', null)).to.be.true;
-      expect(similarityCache.hasSimilarEntries('Nice apartment', undefined)).to.be.true;
-    });
-  });
-});
diff --git a/test/provider/einsAImmobilien.test.js b/test/provider/einsAImmobilien.test.js
index 4efba2a..ad6933a 100644
--- a/test/provider/einsAImmobilien.test.js
+++ b/test/provider/einsAImmobilien.test.js
@@ -5,9 +5,6 @@ import { expect } from 'chai';
 import * as provider from '../../lib/provider/einsAImmobilien.js';
 
 describe('#einsAImmobilien testsuite()', () => {
-  after(() => {
-    similarityCache.stopCacheCleanup();
-  });
   provider.init(providerConfig.einsAImmobilien, [], []);
   it('should test einsAImmobilien provider', async () => {
     const Fredy = await mockFredy();
diff --git a/test/provider/immobilienDe.test.js b/test/provider/immobilienDe.test.js
index 6383bb6..887a06a 100644
--- a/test/provider/immobilienDe.test.js
+++ b/test/provider/immobilienDe.test.js
@@ -5,9 +5,6 @@ import { expect } from 'chai';
 import * as provider from '../../lib/provider/immobilienDe.js';
 
 describe('#immobilien.de testsuite()', () => {
-  after(() => {
-    similarityCache.stopCacheCleanup();
-  });
   provider.init(providerConfig.immobilienDe, [], []);
   it('should test immobilien.de provider', async () => {
     const Fredy = await mockFredy();
diff --git a/test/provider/immonet.test.js b/test/provider/immonet.test.js
index b730c56..5350360 100644
--- a/test/provider/immonet.test.js
+++ b/test/provider/immonet.test.js
@@ -5,10 +5,6 @@ import { expect } from 'chai';
 import * as provider from '../../lib/provider/immonet.js';
 
 describe('#immonet testsuite()', () => {
-  after(() => {
-    similarityCache.stopCacheCleanup();
-  });
-
   it('should test immonet provider', async () => {
     const Fredy = await mockFredy();
     provider.init(providerConfig.immonet, [], []);
diff --git a/test/provider/immoscout.test.js b/test/provider/immoscout.test.js
index ec6911d..322ebc3 100644
--- a/test/provider/immoscout.test.js
+++ b/test/provider/immoscout.test.js
@@ -5,10 +5,6 @@ import { get } from '../mocks/mockNotification.js';
 import * as provider from '../../lib/provider/immoscout.js';
 
 describe('#immoscout provider testsuite()', () => {
-  after(() => {
-    similarityCache.stopCacheCleanup();
-  });
-
   provider.init(providerConfig.immoscout, [], []);
   it('should test immoscout provider', async () => {
     const Fredy = await mockFredy();
diff --git a/test/provider/immoswp.test.js b/test/provider/immoswp.test.js
index 603bba9..f0f987c 100644
--- a/test/provider/immoswp.test.js
+++ b/test/provider/immoswp.test.js
@@ -5,9 +5,6 @@ import { expect } from 'chai';
 import * as provider from '../../lib/provider/immoswp.js';
 
 describe('#immoswp testsuite()', () => {
-  after(() => {
-    similarityCache.stopCacheCleanup();
-  });
   provider.init(providerConfig.immoswp, [], []);
   it('should test immoswp provider', async () => {
     const Fredy = await mockFredy();
diff --git a/test/provider/immowelt.test.js b/test/provider/immowelt.test.js
index fb81f24..2285b71 100644
--- a/test/provider/immowelt.test.js
+++ b/test/provider/immowelt.test.js
@@ -5,10 +5,6 @@ import { expect } from 'chai';
 import * as provider from '../../lib/provider/immowelt.js';
 
 describe('#immowelt testsuite()', () => {
-  after(() => {
-    similarityCache.stopCacheCleanup();
-  });
-
   it('should test immowelt provider', async () => {
     const Fredy = await mockFredy();
     provider.init(providerConfig.immowelt, [], []);
diff --git a/test/provider/kleinanzeigen.test.js b/test/provider/kleinanzeigen.test.js
index b573361..c228790 100644
--- a/test/provider/kleinanzeigen.test.js
+++ b/test/provider/kleinanzeigen.test.js
@@ -5,9 +5,6 @@ import { expect } from 'chai';
 import * as provider from '../../lib/provider/kleinanzeigen.js';
 
 describe('#kleinanzeigen testsuite()', () => {
-  after(() => {
-    similarityCache.stopCacheCleanup();
-  });
   it('should test kleinanzeigen provider', async () => {
     const Fredy = await mockFredy();
     provider.init(providerConfig.kleinanzeigen, [], []);
diff --git a/test/provider/mcMakler.test.js b/test/provider/mcMakler.test.js
index 2dbfa31..b48c40d 100644
--- a/test/provider/mcMakler.test.js
+++ b/test/provider/mcMakler.test.js
@@ -5,10 +5,6 @@ import { expect } from 'chai';
 import * as provider from '../../lib/provider/mcMakler.js';
 
 describe('#mcMakler testsuite()', () => {
-  after(() => {
-    similarityCache.stopCacheCleanup();
-  });
-
   it('should test mcMakler provider', async () => {
     const Fredy = await mockFredy();
     provider.init(providerConfig.mcMakler, []);
diff --git a/test/provider/neubauKompass.test.js b/test/provider/neubauKompass.test.js
index 4682bd0..5e5a445 100644
--- a/test/provider/neubauKompass.test.js
+++ b/test/provider/neubauKompass.test.js
@@ -5,9 +5,6 @@ import { expect } from 'chai';
 import * as provider from '../../lib/provider/neubauKompass.js';
 
 describe('#neubauKompass testsuite()', () => {
-  after(() => {
-    similarityCache.stopCacheCleanup();
-  });
   provider.init(providerConfig.neubauKompass, [], []);
   it('should test neubauKompass provider', async () => {
     const Fredy = await mockFredy();
diff --git a/test/provider/regionalimmobilien24.test.js b/test/provider/regionalimmobilien24.test.js
index 19cbe57..6dafb08 100644
--- a/test/provider/regionalimmobilien24.test.js
+++ b/test/provider/regionalimmobilien24.test.js
@@ -5,10 +5,6 @@ import { expect } from 'chai';
 import * as provider from '../../lib/provider/regionalimmobilien24.js';
 
 describe('#regionalimmobilien24 testsuite()', () => {
-  after(() => {
-    similarityCache.stopCacheCleanup();
-  });
-
   it('should test regionalimmobilien24 provider', async () => {
     const Fredy = await mockFredy();
     provider.init(providerConfig.regionalimmobilien24, []);
diff --git a/test/provider/sparkasse.test.js b/test/provider/sparkasse.test.js
index ac65e4f..0b16c3c 100644
--- a/test/provider/sparkasse.test.js
+++ b/test/provider/sparkasse.test.js
@@ -5,10 +5,6 @@ import { expect } from 'chai';
 import * as provider from '../../lib/provider/sparkasse.js';
 
 describe('#sparkasse testsuite()', () => {
-  after(() => {
-    similarityCache.stopCacheCleanup();
-  });
-
   it('should test sparkasse provider', async () => {
     const Fredy = await mockFredy();
     provider.init(providerConfig.sparkasse, []);
diff --git a/test/provider/wgGesucht.test.js b/test/provider/wgGesucht.test.js
index 116a34f..4bde924 100644
--- a/test/provider/wgGesucht.test.js
+++ b/test/provider/wgGesucht.test.js
@@ -5,9 +5,6 @@ import { expect } from 'chai';
 import * as provider from '../../lib/provider/wgGesucht.js';
 
 describe('#wgGesucht testsuite()', () => {
-  after(() => {
-    similarityCache.stopCacheCleanup();
-  });
   provider.init(providerConfig.wgGesucht, [], []);
   it('should test wgGesucht provider', async () => {
     const Fredy = await mockFredy();
diff --git a/test/similarity/similarity.test.js b/test/similarity/similarity.test.js
deleted file mode 100644
index 418e43e..0000000
--- a/test/similarity/similarity.test.js
+++ /dev/null
@@ -1,30 +0,0 @@
-import { expect } from 'chai';
-import * as similarityCache from '../../lib/services/similarity-check/similarityCache.js';
-
-describe('similarityCheck', () => {
-  it('should return true on duplicate', () => {
-    similarityCache.addCacheEntry('Hello World', 'Test');
-    expect(similarityCache.hasSimilarEntries('Hello World', 'Test')).to.be.true;
-  });
-
-  it('should return true even if one value is null', () => {
-    similarityCache.addCacheEntry('Hello World', null);
-    expect(similarityCache.hasSimilarEntries('Hello World', null)).to.be.true;
-  });
-
-  it('should return true even if one value is an obj', () => {
-    similarityCache.addCacheEntry('Hello World', [{ TR: 'OLOLO' }]);
-    expect(similarityCache.hasSimilarEntries('Hello World', [{ TR: 'OLOLO' }])).to.be.true;
-  });
-
-  it('should return false when no duplicate', () => {
-    similarityCache.addCacheEntry('Hello World__', 'Test');
-    expect(similarityCache.hasSimilarEntries('Hello World___', 'Test')).to.be.false;
-  });
-
-  it('should return false when no duplicate', () => {
-    expect(similarityCache.hasSimilarEntries('Hello World', 'Test')).to.be.true;
-    similarityCache.invalidateAllForTest();
-    expect(similarityCache.hasSimilarEntries('Hello World', 'Test')).to.be.false;
-  });
-});
diff --git a/test/similarity/similarityCache.test.js b/test/similarity/similarityCache.test.js
new file mode 100644
index 0000000..100ea1c
--- /dev/null
+++ b/test/similarity/similarityCache.test.js
@@ -0,0 +1,62 @@
+import { expect } from 'chai';
+import esmock from 'esmock';
+
+// Helper to create module under test with mocks
+async function loadModuleWith({ entries = [] } = {}) {
+  const mod = await esmock('../../lib/services/similarity-check/similarityCache.js', {
+    // Mock the storage to return our controlled entries
+    '../../lib/services/storage/listingsStorage.js': {
+      getAllEntriesFromListings: () => entries,
+    },
+  });
+  return mod;
+}
+
+describe('similarityCache', () => {
+  it('initSimilarityCache builds cache from storage and enables duplicate detection', async () => {
+    const entries = [
+      { title: 'A', price: 1000, address: 'Main 1' },
+      { title: 'B', price: 0, address: 'Zero St' },
+    ];
+
+    const { initSimilarityCache, checkAndAddEntry } = await loadModuleWith({ entries });
+
+    // Initially, duplicates should not be detected for new data
+    expect(checkAndAddEntry({ title: 'X', price: 200, address: 'Y' })).to.equal(false);
+
+    // Now initialize from storage
+    initSimilarityCache();
+
+    // Exact duplicates should be detected
+    expect(checkAndAddEntry({ title: 'A', price: 1000, address: 'Main 1' })).to.equal(true);
+    // Ensure falsy-but-valid price 0 is preserved by hashing and detected as duplicate
+    expect(checkAndAddEntry({ title: 'B', price: 0, address: 'Zero St' })).to.equal(true);
+  });
+
+  it('checkAndAddEntry returns false for new entry then true for duplicate on second call', async () => {
+    const { checkAndAddEntry } = await loadModuleWith();
+
+    const first = checkAndAddEntry({ title: 'C', price: 300, address: 'Road 3' });
+    const second = checkAndAddEntry({ title: 'C', price: 300, address: 'Road 3' });
+
+    expect(first).to.equal(false);
+    expect(second).to.equal(true);
+  });
+
+  it('hashing ignores null/undefined but preserves 0 via behavior', async () => {
+    const { checkAndAddEntry } = await loadModuleWith();
+
+    // Add baseline (null address ignored)
+    const add1 = checkAndAddEntry({ title: 'T', price: 1, address: null });
+    expect(add1).to.equal(false);
+    // Duplicate with undefined address should match
+    const dup = checkAndAddEntry({ title: 'T', price: 1, address: undefined });
+    expect(dup).to.equal(true);
+
+    // Now test that price 0 is preserved (not filtered out)
+    const addZero = checkAndAddEntry({ title: 'Z', price: 0, address: 'Zero' });
+    expect(addZero).to.equal(false);
+    const dupZero = checkAndAddEntry({ title: 'Z', price: 0, address: 'Zero' });
+    expect(dupZero).to.equal(true);
+  });
+});