diff --git a/bundle.js b/bundle.js
index 5a7d0a9..82bfd85 100755
--- a/bundle.js
+++ b/bundle.js
@@ -108,6 +108,7 @@ async function bundleJS(inputDir, outputDir, watch) {
             changes: `${inputDir}/changes.js`,
             settings: `${inputDir}/settings.js`,
             index: `${inputDir}/index.js`,
+            loader: `${inputDir}/model/loader.js`,
         },
         bundle: true,
         sourcemap: true,
diff --git a/site/model/items.js b/site/model/items.js
index b1319b1..89f5a03 100644
--- a/site/model/items.js
+++ b/site/model/items.js
@@ -1,142 +1,6 @@
-const { deltaTime, log, uint16ToDate } = require("../js/misc");
-const { stores, STORE_KEYS } = require("./stores");
 const { Model } = require("./model");
 const { Settings } = require("./settings");
-
-function decompressBinary(buffer) {
-    const objects = [];
-    let offset = 0;
-    const view = new DataView(buffer);
-    const baseDate = new Date("2000-01-01");
-    const textDecoder = new TextDecoder("utf-8");
-
-    const numStores = view.getUint8(offset++);
-    const stores = [];
-    for (let i = 0; i < numStores; i++) {
-        const nameLength = view.getUint16(offset, true);
-        offset += 2;
-        const nameBuffer = new Uint8Array(buffer, offset, nameLength);
-        stores.push(textDecoder.decode(nameBuffer));
-        offset += nameLength;
-    }
-
-    const numWords = view.getUint32(offset, true);
-    offset += 4;
-    const words = new Array(numWords);
-    for (let i = 0; i < numWords; i++) {
-        const nameLength = view.getUint8(offset++);
-        const nameBuffer = new Uint8Array(buffer, offset, nameLength);
-        words[i] = textDecoder.decode(nameBuffer);
-        offset += nameLength;
-    }
-
-    while (offset < buffer.byteLength) {
-        const obj = {};
-        const idLength = view.getUint8(offset++);
-        const idBuffer = new Uint8Array(buffer, offset, idLength);
-        obj.id = textDecoder.decode(idBuffer);
-        offset += idLength;
-
-        const flagsByte = view.getUint8(offset++);
-        obj.bio = (flagsByte & 1) !== 0;
-        obj.isWeighted = (flagsByte & 2) !== 0;
-        if (flagsByte & 4) obj.unit = "ml";
-        if (flagsByte & 8) obj.unit = "g";
-        if (flagsByte & 16) obj.unit = "stk";
-        if (flagsByte & 32) obj.unit = "cm";
-        if (flagsByte & 64) obj.unit = "wg";
-
-        obj.quantity = view.getUint16(offset, true);
-        offset += 2;
-
-        obj.store = stores[view.getUint8(offset++)];
-
-        let name = "";
-        const numTokens = view.getUint8(offset++);
-        for (let i = 0; i < numTokens; i++) {
-            const b1 = view.getUint8(offset++);
-            const b2 = view.getUint8(offset++);
-            const b3 = view.getUint8(offset++);
-            const tokenId = (b3 << 16) | (b2 << 8) | b1;
-            name += words[tokenId];
-            if (i < numTokens - 1) name += " ";
-        }
-        obj.name = name;
-
-        const urlLength = view.getUint16(offset, true);
-        offset += 2;
-        if (urlLength !== 0) {
-            const urlBuffer = new Uint8Array(buffer, offset, urlLength);
-            obj.url = textDecoder.decode(urlBuffer);
-        } else {
-            obj.url = undefined;
-        }
-        offset += urlLength;
-
-        const priceHistoryLength = view.getUint16(offset, true);
-        offset += 2;
-        obj.priceHistory = new Array(priceHistoryLength);
-
-        for (let i = 0; i < priceHistoryLength; i++) {
-            const price = view.getUint16(offset, true) / 100;
-            offset += 2;
-
-            const date = uint16ToDate(view.getUint16(offset, true));
-            offset += 2;
-
-            obj.priceHistory[i] = { date, price };
-        }
-
-        obj.price = obj.priceHistory[0].price;
-
-        objects.push(obj);
-    }
-
-    return objects;
-}
-
-function decompress(compressedItems) {
-    const storeLookup = compressedItems.stores;
-    const data = compressedItems.data;
-    const dates = compressedItems.dates;
-    const numItems = compressedItems.n;
-    const items = new Array(numItems);
-    let i = 0;
-    for (let l = 0; l < numItems; l++) {
-        const store = storeLookup[data[i++]];
-        const id = data[i++];
-        const name = data[i++];
-        const numPrices = data[i++];
-        const prices = new Array(numPrices);
-        for (let j = 0; j < numPrices; j++) {
-            const date = dates[data[i++]];
-            const price = data[i++];
-            prices[j] = {
-                date: date.substring(0, 4) + "-" + date.substring(4, 6) + "-" + date.substring(6, 8),
-                price,
-            };
-        }
-        const unit = data[i++];
-        const quantity = data[i++];
-        const isWeighted = data[i++] == 1;
-        const bio = data[i++] == 1;
-        const url = stores[store].getUrl({ id, name, url: data[i++] });
-
-        items[l] = {
-            store,
-            id,
-            name,
-            price: prices[0].price,
-            priceHistory: prices,
-            isWeighted,
-            unit,
-            quantity,
-            bio,
-            url,
-        };
-    }
-    return items;
-}
+const { loadItems } = require("./loader");
 
 class Items extends Model {
     constructor() {
@@ -163,103 +27,25 @@ class Items extends Model {
         return this._lookup;
     }
 
-    processItems(items) {
-        const lookup = new Set();
-        const start = performance.now();
-        for (const item of items) {
-            lookup[item.store + item.id] = item;
-            item.search = item.name + " " + item.quantity + " " + item.unit;
-            item.search = item.search.toLowerCase().replace(",", ".");
-
-            const unitPriceFactor = item.unit == "g" || item.unit == "ml" ? 1000 : 1;
-            item.unitPrice = (item.price / item.quantity) * unitPriceFactor;
-            item.numPrices = item.priceHistory.length;
-            item.priceOldest = item.priceHistory[item.priceHistory.length - 1].price;
-            item.dateOldest = item.priceHistory[item.priceHistory.length - 1].date;
-            item.date = item.priceHistory[0].date;
-            let highestPriceBefore = -1;
-            let lowestPriceBefore = 100000;
-            for (let i = 0; i < item.priceHistory.length; i++) {
-                const price = item.priceHistory[i];
-                price.unitPrice = (price.price / item.quantity) * unitPriceFactor;
-                if (i == 0) continue;
-                if (i < 10) {
-                    item["price" + i] = price.price;
-                    item["unitPrice" + i] = price.unitPrice;
-                    item["date" + i] = price.date;
-                }
-                highestPriceBefore = Math.max(highestPriceBefore, price.price);
-                lowestPriceBefore = Math.min(lowestPriceBefore, price.price);
-            }
-            if (highestPriceBefore == -1) highestPriceBefore = item.price;
-            if (lowestPriceBefore == 100000) lowestPriceBefore = item.price;
-            item.highestBefore = highestPriceBefore;
-            item.lowestBefore = lowestPriceBefore;
-        }
-
-        items.sort((a, b) => {
-            if (a.store < b.store) {
-                return -1;
-            } else if (a.store > b.store) {
-                return 1;
-            }
-
-            if (a.name < b.name) {
-                return -1;
-            } else if (a.name > b.name) {
-                return 1;
-            }
-
-            return 0;
-        });
-
-        log(`Items - processing ${items.length} items took ${deltaTime(start).toFixed(4)} secs`);
-        this._items = items;
-        this._lookup = lookup;
-    }
-
     async load() {
-        let start = performance.now();
         const settings = new Settings();
-        const compressedItemsPerStore = [];
-        log(`Items - load using JSON: ${settings.useJson}`);
-        for (const store of STORE_KEYS) {
-            compressedItemsPerStore.push(
-                new Promise(async (resolve) => {
-                    let start = performance.now();
-                    try {
-                        const useJSON = settings.useJson;
-                        if (useJSON) {
-                            const response = await fetch(`data/latest-canonical.${store}.compressed.json`);
-                            const json = await response.json();
-                            log(`Items - loading compressed items for ${store} took ${deltaTime(start)} secs`);
-                            start = performance.now();
-                            let items = decompress(json);
-                            log(`Items - Decompressing items for ${store} took ${deltaTime(start)} secs`);
-                            resolve(items);
-                        } else {
-                            const response = await fetch(`data/latest-canonical.${store}.bin.json`);
-                            const binary = await response.arrayBuffer();
-                            log(`Items - loading compressed binary items for ${store} took ${deltaTime(start)} secs`);
-                            start = performance.now();
-                            let items = decompressBinary(binary);
-                            log(`Items - Decompressing items for ${store} took ${deltaTime(start)} secs`);
-                            resolve(items);
-                        }
-                    } catch (e) {
-                        log(`Items - error while loading compressed items for ${store} ${e.message}`);
-                        resolve([]);
-                    }
-                })
-            );
+        if (window.Worker && false) {
+            const self = this;
+            return new Promise((resolve, reject) => {
+                const loader = new Worker("loader.js");
+                loader.onmessage = (event) => {
+                    self._items = event.data.items;
+                    self._lookup = event.data.lookup;
+                    resolve();
+                };
+                loader.postMessage({ settings });
+            });
+        } else {
+            const { items, lookup } = await loadItems(settings);
+            this._items = items;
+            this._lookup = lookup;
         }
-        const items = [].concat(...(await Promise.all(compressedItemsPerStore)));
-        log(`Items - loaded ${items.length} items took ${deltaTime(start).toFixed(4)} secs`);
-
-        this.processItems(items);
-        log(`Items - total loading took ${deltaTime(start).toFixed(4)} secs`);
     }
 }
 
-exports.decompress = decompress;
 exports.Items = Items;
diff --git a/site/model/loader.js b/site/model/loader.js
new file mode 100644
index 0000000..bde19f5
--- /dev/null
+++ b/site/model/loader.js
@@ -0,0 +1,240 @@
+const { deltaTime, log, uint16ToDate } = require("../js/misc");
+const { stores, STORE_KEYS } = require("./stores");
+
+function decompressBinary(buffer) {
+    const objects = [];
+    let offset = 0;
+    const view = new DataView(buffer);
+    const baseDate = new Date("2000-01-01");
+    const textDecoder = new TextDecoder("utf-8");
+
+    const numStores = view.getUint8(offset++);
+    const stores = [];
+    for (let i = 0; i < numStores; i++) {
+        const nameLength = view.getUint16(offset, true);
+        offset += 2;
+        const nameBuffer = new Uint8Array(buffer, offset, nameLength);
+        stores.push(textDecoder.decode(nameBuffer));
+        offset += nameLength;
+    }
+
+    const numWords = view.getUint32(offset, true);
+    offset += 4;
+    const words = new Array(numWords);
+    for (let i = 0; i < numWords; i++) {
+        const nameLength = view.getUint8(offset++);
+        const nameBuffer = new Uint8Array(buffer, offset, nameLength);
+        words[i] = textDecoder.decode(nameBuffer);
+        offset += nameLength;
+    }
+
+    while (offset < buffer.byteLength) {
+        const obj = {};
+        const idLength = view.getUint8(offset++);
+        const idBuffer = new Uint8Array(buffer, offset, idLength);
+        obj.id = textDecoder.decode(idBuffer);
+        offset += idLength;
+
+        const flagsByte = view.getUint8(offset++);
+        obj.bio = (flagsByte & 1) !== 0;
+        obj.isWeighted = (flagsByte & 2) !== 0;
+        if (flagsByte & 4) obj.unit = "ml";
+        if (flagsByte & 8) obj.unit = "g";
+        if (flagsByte & 16) obj.unit = "stk";
+        if (flagsByte & 32) obj.unit = "cm";
+        if (flagsByte & 64) obj.unit = "wg";
+
+        obj.quantity = view.getUint16(offset, true);
+        offset += 2;
+
+        obj.store = stores[view.getUint8(offset++)];
+
+        let name = "";
+        const numTokens = view.getUint8(offset++);
+        for (let i = 0; i < numTokens; i++) {
+            const b1 = view.getUint8(offset++);
+            const b2 = view.getUint8(offset++);
+            const b3 = view.getUint8(offset++);
+            const tokenId = (b3 << 16) | (b2 << 8) | b1;
+            name += words[tokenId];
+            if (i < numTokens - 1) name += " ";
+        }
+        obj.name = name;
+
+        const urlLength = view.getUint16(offset, true);
+        offset += 2;
+        if (urlLength !== 0) {
+            const urlBuffer = new Uint8Array(buffer, offset, urlLength);
+            obj.url = textDecoder.decode(urlBuffer);
+        } else {
+            obj.url = undefined;
+        }
+        offset += urlLength;
+
+        const priceHistoryLength = view.getUint16(offset, true);
+        offset += 2;
+        obj.priceHistory = new Array(priceHistoryLength);
+
+        for (let i = 0; i < priceHistoryLength; i++) {
+            const price = view.getUint16(offset, true) / 100;
+            offset += 2;
+
+            const date = uint16ToDate(view.getUint16(offset, true));
+            offset += 2;
+
+            obj.priceHistory[i] = { date, price };
+        }
+
+        obj.price = obj.priceHistory[0].price;
+
+        objects.push(obj);
+    }
+
+    return objects;
+}
+
+function decompress(compressedItems) {
+    const storeLookup = compressedItems.stores;
+    const data = compressedItems.data;
+    const dates = compressedItems.dates;
+    const numItems = compressedItems.n;
+    const items = new Array(numItems);
+    let i = 0;
+    for (let l = 0; l < numItems; l++) {
+        const store = storeLookup[data[i++]];
+        const id = data[i++];
+        const name = data[i++];
+        const numPrices = data[i++];
+        const prices = new Array(numPrices);
+        for (let j = 0; j < numPrices; j++) {
+            const date = dates[data[i++]];
+            const price = data[i++];
+            prices[j] = {
+                date: date.substring(0, 4) + "-" + date.substring(4, 6) + "-" + date.substring(6, 8),
+                price,
+            };
+        }
+        const unit = data[i++];
+        const quantity = data[i++];
+        const isWeighted = data[i++] == 1;
+        const bio = data[i++] == 1;
+        const url = stores[store].getUrl({ id, name, url: data[i++] });
+
+        items[l] = {
+            store,
+            id,
+            name,
+            price: prices[0].price,
+            priceHistory: prices,
+            isWeighted,
+            unit,
+            quantity,
+            bio,
+            url,
+        };
+    }
+    return items;
+}
+
+function processItems(items) {
+    const lookup = {};
+    const start = performance.now();
+    for (const item of items) {
+        lookup[item.store + item.id] = item;
+        item.search = item.name + " " + item.quantity + " " + item.unit;
+        item.search = item.search.toLowerCase().replace(",", ".");
+
+        const unitPriceFactor = item.unit == "g" || item.unit == "ml" ? 1000 : 1;
+        item.unitPrice = (item.price / item.quantity) * unitPriceFactor;
+        item.numPrices = item.priceHistory.length;
+        item.priceOldest = item.priceHistory[item.priceHistory.length - 1].price;
+        item.dateOldest = item.priceHistory[item.priceHistory.length - 1].date;
+        item.date = item.priceHistory[0].date;
+        let highestPriceBefore = -1;
+        let lowestPriceBefore = 100000;
+        for (let i = 0; i < item.priceHistory.length; i++) {
+            const price = item.priceHistory[i];
+            price.unitPrice = (price.price / item.quantity) * unitPriceFactor;
+            if (i == 0) continue;
+            if (i < 10) {
+                item["price" + i] = price.price;
+                item["unitPrice" + i] = price.unitPrice;
+                item["date" + i] = price.date;
+            }
+            highestPriceBefore = Math.max(highestPriceBefore, price.price);
+            lowestPriceBefore = Math.min(lowestPriceBefore, price.price);
+        }
+        if (highestPriceBefore == -1) highestPriceBefore = item.price;
+        if (lowestPriceBefore == 100000) lowestPriceBefore = item.price;
+        item.highestBefore = highestPriceBefore;
+        item.lowestBefore = lowestPriceBefore;
+    }
+
+    items.sort((a, b) => {
+        if (a.store < b.store) {
+            return -1;
+        } else if (a.store > b.store) {
+            return 1;
+        }
+
+        if (a.name < b.name) {
+            return -1;
+        } else if (a.name > b.name) {
+            return 1;
+        }
+
+        return 0;
+    });
+
+    log(`Items - processing ${items.length} items took ${deltaTime(start).toFixed(4)} secs`);
+    return { items, lookup };
+}
+
+exports.loadItems = async (settings) => {
+    let start = performance.now();
+    const compressedItemsPerStore = [];
+    log(`Items - load using JSON: ${settings.useJson}`);
+    for (const store of STORE_KEYS) {
+        compressedItemsPerStore.push(
+            new Promise(async (resolve) => {
+                let start = performance.now();
+                try {
+                    const useJSON = settings.useJson;
+                    if (useJSON) {
+                        const response = await fetch(`data/latest-canonical.${store}.compressed.json`);
+                        const json = await response.json();
+                        log(`Items - loading compressed items for ${store} took ${deltaTime(start)} secs`);
+                        start = performance.now();
+                        let items = decompress(json);
+                        log(`Items - Decompressing items for ${store} took ${deltaTime(start)} secs`);
+                        resolve(items);
+                    } else {
+                        const response = await fetch(`data/latest-canonical.${store}.bin.json`);
+                        const binary = await response.arrayBuffer();
+                        log(`Items - loading compressed binary items for ${store} took ${deltaTime(start)} secs`);
+                        start = performance.now();
+                        let items = decompressBinary(binary);
+                        log(`Items - Decompressing items for ${store} took ${deltaTime(start)} secs`);
+                        resolve(items);
+                    }
+                } catch (e) {
+                    log(`Items - error while loading compressed items for ${store} ${e.message}`);
+                    resolve([]);
+                }
+            })
+        );
+    }
+    const items = [].concat(...(await Promise.all(compressedItemsPerStore)));
+    log(`Items - loaded ${items.length} items took ${deltaTime(start).toFixed(4)} secs`);
+
+    const result = processItems(items);
+    log(`Items - total loading took ${deltaTime(start).toFixed(4)} secs`);
+
+    return result;
+};
+
+onmessage = async (event) => {
+    const settings = event.data.settings;
+    const result = await exports.loadItems(settings);
+    postMessage(result);
+};