diff --git a/src/lib/data/db.test.ts b/src/lib/data/db.test.ts
new file mode 100644
index 0000000..0b12a08
--- /dev/null
+++ b/src/lib/data/db.test.ts
@@ -0,0 +1,110 @@
+import { describe, it, expect, beforeEach } from 'vitest';
+import { deleteDB } from 'idb';
+import { getDB, resetDBPromise } from '$lib/data/db';
+
+beforeEach(async () => {
+	await resetDBPromise();
+	await deleteDB('solidhaus');
+});
+
+describe('getDB', () => {
+	it('returns a valid database instance', async () => {
+		const db = await getDB();
+		expect(db).toBeDefined();
+		expect(db.name).toBe('solidhaus');
+		expect(db.version).toBe(1);
+	});
+
+	it('returns the same DB instance when called multiple times (singleton)', async () => {
+		const db1 = await getDB();
+		const db2 = await getDB();
+		expect(db1).toBe(db2);
+	});
+
+	describe('object stores', () => {
+		it('has the items store', async () => {
+			const db = await getDB();
+			expect(db.objectStoreNames.contains('items')).toBe(true);
+		});
+
+		it('has the locations store', async () => {
+			const db = await getDB();
+			expect(db.objectStoreNames.contains('locations')).toBe(true);
+		});
+
+		it('has the sightings store', async () => {
+			const db = await getDB();
+			expect(db.objectStoreNames.contains('sightings')).toBe(true);
+		});
+
+		it('has the photos store', async () => {
+			const db = await getDB();
+			expect(db.objectStoreNames.contains('photos')).toBe(true);
+		});
+
+		it('has the preGeneratedIds store', async () => {
+			const db = await getDB();
+			expect(db.objectStoreNames.contains('preGeneratedIds')).toBe(true);
+		});
+
+		it('has the settings store', async () => {
+			const db = await getDB();
+			expect(db.objectStoreNames.contains('settings')).toBe(true);
+		});
+
+		it('has exactly 6 object stores', async () => {
+			const db = await getDB();
+			expect(db.objectStoreNames.length).toBe(6);
+		});
+	});
+
+	describe('indexes', () => {
+		it('has all indexes on the items store', async () => {
+			const db = await getDB();
+			const tx = db.transaction('items', 'readonly');
+			const store = tx.objectStore('items');
+			expect(store.indexNames.contains('by-name')).toBe(true);
+			expect(store.indexNames.contains('by-category')).toBe(true);
+			expect(store.indexNames.contains('by-location')).toBe(true);
+			expect(store.indexNames.contains('by-type')).toBe(true);
+			expect(store.indexNames.contains('by-custody')).toBe(true);
+			await tx.done;
+		});
+
+		it('has all indexes on the locations store', async () => {
+			const db = await getDB();
+			const tx = db.transaction('locations', 'readonly');
+			const store = tx.objectStore('locations');
+			expect(store.indexNames.contains('by-parent')).toBe(true);
+			expect(store.indexNames.contains('by-name')).toBe(true);
+			await tx.done;
+		});
+
+		it('has all indexes on the sightings store', async () => {
+			const db = await getDB();
+			const tx = db.transaction('sightings', 'readonly');
+			const store = tx.objectStore('sightings');
+			expect(store.indexNames.contains('by-item')).toBe(true);
+			expect(store.indexNames.contains('by-location')).toBe(true);
+			expect(store.indexNames.contains('by-timestamp')).toBe(true);
+			await tx.done;
+		});
+
+		it('has the by-item index on the photos store', async () => {
+			const db = await getDB();
+			const tx = db.transaction('photos', 'readonly');
+			const store = tx.objectStore('photos');
+			expect(store.indexNames.contains('by-item')).toBe(true);
+			await tx.done;
+		});
+
+		it('has all indexes on the preGeneratedIds store', async () => {
+			const db = await getDB();
+			const tx = db.transaction('preGeneratedIds', 'readonly');
+			const store = tx.objectStore('preGeneratedIds');
+			expect(store.indexNames.contains('by-batch')).toBe(true);
+			expect(store.indexNames.contains('by-assigned')).toBe(true);
+			await tx.done;
+		});
+	});
+});
diff --git a/src/lib/data/db.ts b/src/lib/data/db.ts
new file mode 100644
index 0000000..0f498d3
--- /dev/null
+++ b/src/lib/data/db.ts
@@ -0,0 +1,109 @@
+import { openDB, type IDBPDatabase, type DBSchema } from 'idb';
+
+interface SolidHausDB extends DBSchema {
+	items: {
+		key: string;
+		value: import('$lib/types').Item;
+		indexes: {
+			'by-name': string;
+			'by-category': string;
+			'by-location': string;
+			'by-type': string;
+			'by-custody': string;
+		};
+	};
+	locations: {
+		key: string;
+		value: import('$lib/types').Location;
+		indexes: {
+			'by-parent': string;
+			'by-name': string;
+		};
+	};
+	sightings: {
+		key: string;
+		value: import('$lib/types').Sighting;
+		indexes: {
+			'by-item': string;
+			'by-location': string;
+			'by-timestamp': string;
+		};
+	};
+	photos: {
+		key: string;
+		value: import('$lib/types').Photo;
+		indexes: {
+			'by-item': string;
+		};
+	};
+	preGeneratedIds: {
+		key: string;
+		value: import('$lib/types').PreGeneratedId;
+		indexes: {
+			'by-batch': string;
+			'by-assigned': string;
+		};
+	};
+	settings: {
+		key: string;
+		value: {
+			key: string;
+			value: unknown;
+		};
+	};
+}
+
+export type { SolidHausDB };
+
+const DB_NAME = 'solidhaus';
+const DB_VERSION = 1;
+
+let dbPromise: Promise<IDBPDatabase<SolidHausDB>> | null = null;
+
+export function getDB(): Promise<IDBPDatabase<SolidHausDB>> {
+	if (!dbPromise) {
+		dbPromise = openDB<SolidHausDB>(DB_NAME, DB_VERSION, {
+			upgrade(db) {
+				// Items
+				const itemStore = db.createObjectStore('items', { keyPath: 'shortId' });
+				itemStore.createIndex('by-name', 'name');
+				itemStore.createIndex('by-category', 'category');
+				itemStore.createIndex('by-location', 'lastSeenAt');
+				itemStore.createIndex('by-type', 'itemType');
+				itemStore.createIndex('by-custody', 'custodyState');
+
+				// Locations
+				const locStore = db.createObjectStore('locations', { keyPath: 'id' });
+				locStore.createIndex('by-parent', 'parentId');
+				locStore.createIndex('by-name', 'name');
+
+				// Sightings
+				const sightStore = db.createObjectStore('sightings', { keyPath: 'id' });
+				sightStore.createIndex('by-item', 'itemId');
+				sightStore.createIndex('by-location', 'locationId');
+				sightStore.createIndex('by-timestamp', 'timestamp');
+
+				// Photos
+				const photoStore = db.createObjectStore('photos', { keyPath: 'id' });
+				photoStore.createIndex('by-item', 'itemId');
+
+				// Pre-generated IDs
+				const pregenStore = db.createObjectStore('preGeneratedIds', { keyPath: 'id' });
+				pregenStore.createIndex('by-batch', 'batchId');
+				pregenStore.createIndex('by-assigned', 'assignedTo');
+
+				// Settings
+				db.createObjectStore('settings', { keyPath: 'key' });
+			},
+		});
+	}
+	return dbPromise;
+}
+
+export async function resetDBPromise(): Promise<void> {
+	if (dbPromise) {
+		const db = await dbPromise;
+		db.close();
+		dbPromise = null;
+	}
+}
diff --git a/src/lib/data/items.test.ts b/src/lib/data/items.test.ts
new file mode 100644
index 0000000..4027fb3
--- /dev/null
+++ b/src/lib/data/items.test.ts
@@ -0,0 +1,223 @@
+import { describe, it, expect, beforeEach } from 'vitest';
+import { deleteDB } from 'idb';
+import { resetDBPromise } from '$lib/data/db';
+import {
+	createItem,
+	getAllItems,
+	getItemById,
+	updateItem,
+	removeItem,
+	getItemsByCategory,
+	getItemsByType,
+	getItemsByCustodyState,
+	getItemsByLocation,
+} from '$lib/data/items';
+import type { Item } from '$lib/types';
+
+function makeItem(overrides: Partial<Item> = {}): Item {
+	const now = new Date().toISOString();
+	return {
+		shortId: 'abc1234',
+		name: 'Test Hammer',
+		description: 'A sturdy claw hammer',
+		category: 'tools',
+		brand: 'Stanley',
+		serialNumber: 'SN-00123',
+		color: 'yellow',
+		purchaseDate: '2024-06-15',
+		itemType: 'durable',
+		currentQuantity: null,
+		originalQuantity: null,
+		quantityUnit: null,
+		lowThreshold: null,
+		expiryDate: null,
+		barcodeFormat: 'qr',
+		barcodeUri: 'https://haus.toph.so/abc1234',
+		photoIds: [],
+		lastSeenAt: 'werkstatt',
+		lastSeenTimestamp: now,
+		lastUsedAt: null,
+		supposedToBeAt: 'werkstatt',
+		locationConfidence: 'confirmed',
+		custodyState: 'checked-in',
+		checkedOutSince: null,
+		checkedOutReason: null,
+		checkedOutFrom: null,
+		checkedOutTo: null,
+		checkedOutNote: null,
+		storageTier: 'hot',
+		storageContainerId: null,
+		storageContainerLabel: null,
+		labelPrinted: false,
+		labelPrintedAt: null,
+		labelBatchId: null,
+		createdAt: now,
+		updatedAt: now,
+		tags: ['hand-tool'],
+		createdBy: null,
+		...overrides,
+	};
+}
+
+beforeEach(async () => {
+	await resetDBPromise();
+	await deleteDB('solidhaus');
+});
+
+describe('createItem', () => {
+	it('creates an item and returns it', async () => {
+		const item = makeItem();
+		const result = await createItem(item);
+		expect(result).toEqual(item);
+	});
+
+	it('persists the item in the database', async () => {
+		const item = makeItem();
+		await createItem(item);
+		const fetched = await getItemById('abc1234');
+		expect(fetched).toEqual(item);
+	});
+
+	it('creates multiple items with different IDs', async () => {
+		const item1 = makeItem({ shortId: 'item001' });
+		const item2 = makeItem({ shortId: 'item002', name: 'Screwdriver' });
+		await createItem(item1);
+		await createItem(item2);
+		const all = await getAllItems();
+		expect(all).toHaveLength(2);
+	});
+});
+
+describe('getAllItems', () => {
+	it('returns an empty array when no items exist', async () => {
+		const items = await getAllItems();
+		expect(items).toEqual([]);
+	});
+
+	it('returns all created items', async () => {
+		await createItem(makeItem({ shortId: 'aaa1111' }));
+		await createItem(makeItem({ shortId: 'bbb2222' }));
+		await createItem(makeItem({ shortId: 'ccc3333' }));
+		const items = await getAllItems();
+		expect(items).toHaveLength(3);
+		const ids = items.map((i) => i.shortId);
+		expect(ids).toContain('aaa1111');
+		expect(ids).toContain('bbb2222');
+		expect(ids).toContain('ccc3333');
+	});
+});
+
+describe('getItemById', () => {
+	it('returns the correct item', async () => {
+		const item = makeItem({ shortId: 'xyz7890', name: 'Drill' });
+		await createItem(item);
+		const result = await getItemById('xyz7890');
+		expect(result).toBeDefined();
+		expect(result!.name).toBe('Drill');
+	});
+
+	it('returns undefined for a non-existent ID', async () => {
+		const result = await getItemById('notreal');
+		expect(result).toBeUndefined();
+	});
+});
+
+describe('updateItem', () => {
+	it('updates specified fields on an existing item', async () => {
+		await createItem(makeItem({ shortId: 'upd0001', name: 'Old Name' }));
+		const result = await updateItem('upd0001', { name: 'New Name' });
+		expect(result).toBeDefined();
+		expect(result!.name).toBe('New Name');
+	});
+
+	it('sets updatedAt to a new timestamp', async () => {
+		const originalDate = '2024-01-01T00:00:00.000Z';
+		await createItem(makeItem({ shortId: 'upd0002', updatedAt: originalDate }));
+		const result = await updateItem('upd0002', { name: 'Changed' });
+		expect(result).toBeDefined();
+		expect(result!.updatedAt).not.toBe(originalDate);
+		// The new updatedAt should be a valid ISO string and more recent
+		expect(new Date(result!.updatedAt).getTime()).toBeGreaterThan(
+			new Date(originalDate).getTime()
+		);
+	});
+
+	it('persists the update in the database', async () => {
+		await createItem(makeItem({ shortId: 'upd0003', category: 'tools' }));
+		await updateItem('upd0003', { category: 'electronics' });
+		const fetched = await getItemById('upd0003');
+		expect(fetched!.category).toBe('electronics');
+	});
+
+	it('returns undefined when updating a non-existent item', async () => {
+		const result = await updateItem('noexist', { name: 'Nope' });
+		expect(result).toBeUndefined();
+	});
+
+	it('does not modify fields that are not in the updates', async () => {
+		await createItem(makeItem({ shortId: 'upd0004', name: 'Hammer', brand: 'Stanley' }));
+		await updateItem('upd0004', { name: 'Mallet' });
+		const fetched = await getItemById('upd0004');
+		expect(fetched!.name).toBe('Mallet');
+		expect(fetched!.brand).toBe('Stanley');
+	});
+});
+
+describe('removeItem', () => {
+	it('deletes an item from the database', async () => {
+		await createItem(makeItem({ shortId: 'del0001' }));
+		await removeItem('del0001');
+		const result = await getItemById('del0001');
+		expect(result).toBeUndefined();
+	});
+
+	it('does not throw when removing a non-existent item', async () => {
+		await expect(removeItem('nonexistent')).resolves.toBeUndefined();
+	});
+
+	it('only removes the specified item', async () => {
+		await createItem(makeItem({ shortId: 'keep001' }));
+		await createItem(makeItem({ shortId: 'del0002' }));
+		await removeItem('del0002');
+		const all = await getAllItems();
+		expect(all).toHaveLength(1);
+		expect(all[0].shortId).toBe('keep001');
+	});
+});
+
+describe('index queries', () => {
+	it('getItemsByCategory returns items matching the category', async () => {
+		await createItem(makeItem({ shortId: 'cat0001', category: 'tools' }));
+		await createItem(makeItem({ shortId: 'cat0002', category: 'electronics' }));
+		await createItem(makeItem({ shortId: 'cat0003', category: 'tools' }));
+		const tools = await getItemsByCategory('tools');
+		expect(tools).toHaveLength(2);
+		expect(tools.every((i) => i.category === 'tools')).toBe(true);
+	});
+
+	it('getItemsByType returns items matching the item type', async () => {
+		await createItem(makeItem({ shortId: 'typ0001', itemType: 'consumable' }));
+		await createItem(makeItem({ shortId: 'typ0002', itemType: 'durable' }));
+		const consumables = await getItemsByType('consumable');
+		expect(consumables).toHaveLength(1);
+		expect(consumables[0].shortId).toBe('typ0001');
+	});
+
+	it('getItemsByCustodyState returns items matching the custody state', async () => {
+		await createItem(makeItem({ shortId: 'cus0001', custodyState: 'checked-in' }));
+		await createItem(makeItem({ shortId: 'cus0002', custodyState: 'checked-out' }));
+		await createItem(makeItem({ shortId: 'cus0003', custodyState: 'checked-out' }));
+		const checkedOut = await getItemsByCustodyState('checked-out');
+		expect(checkedOut).toHaveLength(2);
+		expect(checkedOut.every((i) => i.custodyState === 'checked-out')).toBe(true);
+	});
+
+	it('getItemsByLocation returns items at a given location', async () => {
+		await createItem(makeItem({ shortId: 'loc0001', lastSeenAt: 'kueche' }));
+		await createItem(makeItem({ shortId: 'loc0002', lastSeenAt: 'buero' }));
+		await createItem(makeItem({ shortId: 'loc0003', lastSeenAt: 'kueche' }));
+		const inKueche = await getItemsByLocation('kueche');
+		expect(inKueche).toHaveLength(2);
+		expect(inKueche.every((i) => i.lastSeenAt === 'kueche')).toBe(true);
+	});
+});
diff --git a/src/lib/data/items.ts b/src/lib/data/items.ts
new file mode 100644
index 0000000..7d8bf5d
--- /dev/null
+++ b/src/lib/data/items.ts
@@ -0,0 +1,52 @@
+import { getDB } from './db';
+import type { Item } from '$lib/types';
+
+export async function getAllItems(): Promise<Item[]> {
+	const db = await getDB();
+	return db.getAll('items');
+}
+
+export async function getItemById(shortId: string): Promise<Item | undefined> {
+	const db = await getDB();
+	return db.get('items', shortId);
+}
+
+export async function createItem(item: Item): Promise<Item> {
+	const db = await getDB();
+	await db.put('items', item);
+	return item;
+}
+
+export async function updateItem(shortId: string, updates: Partial<Item>): Promise<Item | undefined> {
+	const db = await getDB();
+	const existing = await db.get('items', shortId);
+	if (!existing) return undefined;
+	const updated = { ...existing, ...updates, updatedAt: new Date().toISOString() };
+	await db.put('items', updated);
+	return updated;
+}
+
+export async function removeItem(shortId: string): Promise<void> {
+	const db = await getDB();
+	await db.delete('items', shortId);
+}
+
+export async function getItemsByCategory(category: string): Promise<Item[]> {
+	const db = await getDB();
+	return db.getAllFromIndex('items', 'by-category', category);
+}
+
+export async function getItemsByType(itemType: string): Promise<Item[]> {
+	const db = await getDB();
+	return db.getAllFromIndex('items', 'by-type', itemType);
+}
+
+export async function getItemsByCustodyState(state: string): Promise<Item[]> {
+	const db = await getDB();
+	return db.getAllFromIndex('items', 'by-custody', state);
+}
+
+export async function getItemsByLocation(locationId: string): Promise<Item[]> {
+	const db = await getDB();
+	return db.getAllFromIndex('items', 'by-location', locationId);
+}
diff --git a/src/lib/data/labels.test.ts b/src/lib/data/labels.test.ts
new file mode 100644
index 0000000..6d58c01
--- /dev/null
+++ b/src/lib/data/labels.test.ts
@@ -0,0 +1,207 @@
+import { describe, it, expect, beforeEach } from 'vitest';
+import { deleteDB } from 'idb';
+import { resetDBPromise, getDB } from '$lib/data/db';
+import {
+	createPreGeneratedId,
+	getUnassignedIds,
+	assignIdToItem,
+	getIdsByBatch,
+	generateBatch,
+} from '$lib/data/labels';
+import type { PreGeneratedId } from '$lib/types';
+
+function makePreGeneratedId(overrides: Partial<PreGeneratedId> = {}): PreGeneratedId {
+	return {
+		id: 'tst1234',
+		generatedAt: new Date().toISOString(),
+		assignedTo: null,
+		batchId: 'batch-001',
+		...overrides,
+	};
+}
+
+beforeEach(async () => {
+	await resetDBPromise();
+	await deleteDB('solidhaus');
+});
+
+describe('createPreGeneratedId', () => {
+	it('creates a pre-generated ID entry and returns it', async () => {
+		const entry = makePreGeneratedId();
+		const result = await createPreGeneratedId(entry);
+		expect(result).toEqual(entry);
+	});
+
+	it('persists the entry in the database', async () => {
+		const entry = makePreGeneratedId({ id: 'per1234' });
+		await createPreGeneratedId(entry);
+		const db = await getDB();
+		const stored = await db.get('preGeneratedIds', 'per1234');
+		expect(stored).toBeDefined();
+		expect(stored!.id).toBe('per1234');
+	});
+
+	it('stores all fields correctly', async () => {
+		const entry = makePreGeneratedId({
+			id: 'fld1234',
+			batchId: 'batch-xyz',
+			assignedTo: null,
+		});
+		await createPreGeneratedId(entry);
+		const db = await getDB();
+		const stored = await db.get('preGeneratedIds', 'fld1234');
+		expect(stored!.batchId).toBe('batch-xyz');
+		expect(stored!.assignedTo).toBeNull();
+		expect(stored!.generatedAt).toBeDefined();
+	});
+});
+
+describe('getUnassignedIds', () => {
+	it('returns entries that have no assignedTo value', async () => {
+		await createPreGeneratedId(makePreGeneratedId({ id: 'free001', assignedTo: null }));
+		await createPreGeneratedId(makePreGeneratedId({ id: 'free002', assignedTo: null }));
+		await createPreGeneratedId(makePreGeneratedId({ id: 'used001', assignedTo: 'item-abc' }));
+
+		const unassigned = await getUnassignedIds();
+		expect(unassigned).toHaveLength(2);
+		const ids = unassigned.map((e) => e.id);
+		expect(ids).toContain('free001');
+		expect(ids).toContain('free002');
+	});
+
+	it('returns an empty array when all IDs are assigned', async () => {
+		await createPreGeneratedId(makePreGeneratedId({ id: 'u001', assignedTo: 'item-1' }));
+		await createPreGeneratedId(makePreGeneratedId({ id: 'u002', assignedTo: 'item-2' }));
+		const unassigned = await getUnassignedIds();
+		expect(unassigned).toEqual([]);
+	});
+
+	it('returns an empty array when no entries exist', async () => {
+		const unassigned = await getUnassignedIds();
+		expect(unassigned).toEqual([]);
+	});
+
+	it('returns all entries when none are assigned', async () => {
+		await createPreGeneratedId(makePreGeneratedId({ id: 'all001' }));
+		await createPreGeneratedId(makePreGeneratedId({ id: 'all002' }));
+		await createPreGeneratedId(makePreGeneratedId({ id: 'all003' }));
+		const unassigned = await getUnassignedIds();
+		expect(unassigned).toHaveLength(3);
+	});
+});
+
+describe('assignIdToItem', () => {
+	it('assigns a pre-generated ID to an item', async () => {
+		await createPreGeneratedId(makePreGeneratedId({ id: 'asn001', assignedTo: null }));
+		const result = await assignIdToItem('asn001', 'myitem1');
+		expect(result).toBeDefined();
+		expect(result!.assignedTo).toBe('myitem1');
+	});
+
+	it('persists the assignment in the database', async () => {
+		await createPreGeneratedId(makePreGeneratedId({ id: 'asn002', assignedTo: null }));
+		await assignIdToItem('asn002', 'myitem2');
+		const db = await getDB();
+		const stored = await db.get('preGeneratedIds', 'asn002');
+		expect(stored!.assignedTo).toBe('myitem2');
+	});
+
+	it('returns undefined when the ID does not exist', async () => {
+		const result = await assignIdToItem('nonexist', 'myitem3');
+		expect(result).toBeUndefined();
+	});
+
+	it('makes the ID no longer appear in unassigned list', async () => {
+		await createPreGeneratedId(makePreGeneratedId({ id: 'asn003', assignedTo: null }));
+		await createPreGeneratedId(makePreGeneratedId({ id: 'asn004', assignedTo: null }));
+		await assignIdToItem('asn003', 'target-item');
+
+		const unassigned = await getUnassignedIds();
+		const ids = unassigned.map((e) => e.id);
+		expect(ids).not.toContain('asn003');
+		expect(ids).toContain('asn004');
+	});
+});
+
+describe('getIdsByBatch', () => {
+	it('returns all IDs belonging to a specific batch', async () => {
+		await createPreGeneratedId(makePreGeneratedId({ id: 'bat001', batchId: 'batch-A' }));
+		await createPreGeneratedId(makePreGeneratedId({ id: 'bat002', batchId: 'batch-A' }));
+		await createPreGeneratedId(makePreGeneratedId({ id: 'bat003', batchId: 'batch-B' }));
+
+		const batchA = await getIdsByBatch('batch-A');
+		expect(batchA).toHaveLength(2);
+		expect(batchA.every((e) => e.batchId === 'batch-A')).toBe(true);
+	});
+
+	it('returns an empty array when no IDs match the batch', async () => {
+		await createPreGeneratedId(makePreGeneratedId({ id: 'bat004', batchId: 'batch-C' }));
+		const result = await getIdsByBatch('batch-nonexistent');
+		expect(result).toEqual([]);
+	});
+
+	it('returns an empty array when the store is empty', async () => {
+		const result = await getIdsByBatch('any-batch');
+		expect(result).toEqual([]);
+	});
+});
+
+describe('generateBatch', () => {
+	it('creates the specified number of IDs', async () => {
+		const entries = await generateBatch(5, 'gen-batch-1');
+		expect(entries).toHaveLength(5);
+	});
+
+	it('returns entries with the correct batchId', async () => {
+		const entries = await generateBatch(3, 'gen-batch-2');
+		expect(entries.every((e) => e.batchId === 'gen-batch-2')).toBe(true);
+	});
+
+	it('returns entries with null assignedTo', async () => {
+		const entries = await generateBatch(2, 'gen-batch-3');
+		expect(entries.every((e) => e.assignedTo === null)).toBe(true);
+	});
+
+	it('generates unique IDs for each entry', async () => {
+		const entries = await generateBatch(10, 'gen-batch-4');
+		const ids = entries.map((e) => e.id);
+		const uniqueIds = new Set(ids);
+		expect(uniqueIds.size).toBe(10);
+	});
+
+	it('persists all generated entries in the database', async () => {
+		await generateBatch(4, 'gen-batch-5');
+		const stored = await getIdsByBatch('gen-batch-5');
+		expect(stored).toHaveLength(4);
+	});
+
+	it('sets generatedAt on all entries', async () => {
+		const entries = await generateBatch(2, 'gen-batch-6');
+		for (const entry of entries) {
+			expect(entry.generatedAt).toBeDefined();
+			expect(() => new Date(entry.generatedAt)).not.toThrow();
+		}
+	});
+
+	it('generates IDs with the expected format (7-char nanoid alphabet)', async () => {
+		const entries = await generateBatch(5, 'gen-batch-7');
+		const validChars = /^[23456789a-hjkmnp-z]{7}$/;
+		for (const entry of entries) {
+			expect(entry.id).toMatch(validChars);
+		}
+	});
+
+	it('handles generating zero IDs', async () => {
+		const entries = await generateBatch(0, 'gen-batch-empty');
+		expect(entries).toHaveLength(0);
+	});
+
+	it('can generate multiple batches independently', async () => {
+		await generateBatch(3, 'batch-x');
+		await generateBatch(4, 'batch-y');
+		const batchX = await getIdsByBatch('batch-x');
+		const batchY = await getIdsByBatch('batch-y');
+		expect(batchX).toHaveLength(3);
+		expect(batchY).toHaveLength(4);
+	});
+});
diff --git a/src/lib/data/labels.ts b/src/lib/data/labels.ts
new file mode 100644
index 0000000..e4cc5eb
--- /dev/null
+++ b/src/lib/data/labels.ts
@@ -0,0 +1,52 @@
+import { getDB } from './db';
+import type { PreGeneratedId } from '$lib/types';
+import { generateItemId } from '$lib/utils/id';
+
+export async function createPreGeneratedId(entry: PreGeneratedId): Promise<PreGeneratedId> {
+	const db = await getDB();
+	await db.put('preGeneratedIds', entry);
+	return entry;
+}
+
+export async function getUnassignedIds(): Promise<PreGeneratedId[]> {
+	const db = await getDB();
+	const all = await db.getAllFromIndex('preGeneratedIds', 'by-assigned', '');
+	// Also get nulls — by-assigned index may not store null correctly, so filter
+	const allIds = await db.getAll('preGeneratedIds');
+	return allIds.filter((entry) => !entry.assignedTo);
+}
+
+export async function assignIdToItem(id: string, itemShortId: string): Promise<PreGeneratedId | undefined> {
+	const db = await getDB();
+	const entry = await db.get('preGeneratedIds', id);
+	if (!entry) return undefined;
+	const updated = { ...entry, assignedTo: itemShortId };
+	await db.put('preGeneratedIds', updated);
+	return updated;
+}
+
+export async function getIdsByBatch(batchId: string): Promise<PreGeneratedId[]> {
+	const db = await getDB();
+	return db.getAllFromIndex('preGeneratedIds', 'by-batch', batchId);
+}
+
+export async function generateBatch(count: number, batchId: string): Promise<PreGeneratedId[]> {
+	const db = await getDB();
+	const now = new Date().toISOString();
+	const entries: PreGeneratedId[] = [];
+
+	const tx = db.transaction('preGeneratedIds', 'readwrite');
+	for (let i = 0; i < count; i++) {
+		const entry: PreGeneratedId = {
+			id: generateItemId(),
+			generatedAt: now,
+			assignedTo: null,
+			batchId,
+		};
+		await tx.store.put(entry);
+		entries.push(entry);
+	}
+	await tx.done;
+
+	return entries;
+}
diff --git a/src/lib/data/locations.test.ts b/src/lib/data/locations.test.ts
new file mode 100644
index 0000000..5f44bff
--- /dev/null
+++ b/src/lib/data/locations.test.ts
@@ -0,0 +1,211 @@
+import { describe, it, expect, beforeEach } from 'vitest';
+import { deleteDB } from 'idb';
+import { resetDBPromise } from '$lib/data/db';
+import {
+	createLocation,
+	getAllLocations,
+	getLocationById,
+	updateLocation,
+	removeLocation,
+	getLocationsByParent,
+	seedDefaultLocations,
+} from '$lib/data/locations';
+import type { Location } from '$lib/types';
+
+function makeLocation(overrides: Partial<Location> = {}): Location {
+	const now = new Date().toISOString();
+	return {
+		id: 'test-room',
+		name: 'Test Room',
+		description: 'A room for testing',
+		parentId: null,
+		locationType: 'room',
+		defaultStorageTier: null,
+		sortOrder: 0,
+		createdAt: now,
+		updatedAt: now,
+		...overrides,
+	};
+}
+
+beforeEach(async () => {
+	await resetDBPromise();
+	await deleteDB('solidhaus');
+});
+
+describe('createLocation', () => {
+	it('creates a location and returns it', async () => {
+		const loc = makeLocation();
+		const result = await createLocation(loc);
+		expect(result).toEqual(loc);
+	});
+
+	it('persists the location in the database', async () => {
+		const loc = makeLocation({ id: 'garage', name: 'Garage' });
+		await createLocation(loc);
+		const fetched = await getLocationById('garage');
+		expect(fetched).toEqual(loc);
+	});
+});
+
+describe('getAllLocations', () => {
+	it('returns an empty array when no locations exist', async () => {
+		const locations = await getAllLocations();
+		expect(locations).toEqual([]);
+	});
+
+	it('returns all created locations', async () => {
+		await createLocation(makeLocation({ id: 'loc-a', name: 'Room A' }));
+		await createLocation(makeLocation({ id: 'loc-b', name: 'Room B' }));
+		const locations = await getAllLocations();
+		expect(locations).toHaveLength(2);
+	});
+});
+
+describe('getLocationById', () => {
+	it('returns the correct location', async () => {
+		const loc = makeLocation({ id: 'kitchen', name: 'Kitchen' });
+		await createLocation(loc);
+		const result = await getLocationById('kitchen');
+		expect(result).toBeDefined();
+		expect(result!.name).toBe('Kitchen');
+	});
+
+	it('returns undefined for a non-existent ID', async () => {
+		const result = await getLocationById('does-not-exist');
+		expect(result).toBeUndefined();
+	});
+});
+
+describe('updateLocation', () => {
+	it('updates specified fields on an existing location', async () => {
+		await createLocation(makeLocation({ id: 'upd-loc', name: 'Old Name' }));
+		const result = await updateLocation('upd-loc', { name: 'New Name' });
+		expect(result).toBeDefined();
+		expect(result!.name).toBe('New Name');
+	});
+
+	it('sets updatedAt to a new timestamp', async () => {
+		const oldDate = '2023-01-01T00:00:00.000Z';
+		await createLocation(makeLocation({ id: 'upd-loc2', updatedAt: oldDate }));
+		const result = await updateLocation('upd-loc2', { description: 'Updated' });
+		expect(result).toBeDefined();
+		expect(new Date(result!.updatedAt).getTime()).toBeGreaterThan(new Date(oldDate).getTime());
+	});
+
+	it('persists the update in the database', async () => {
+		await createLocation(makeLocation({ id: 'upd-loc3', description: 'Before' }));
+		await updateLocation('upd-loc3', { description: 'After' });
+		const fetched = await getLocationById('upd-loc3');
+		expect(fetched!.description).toBe('After');
+	});
+
+	it('returns undefined when updating a non-existent location', async () => {
+		const result = await updateLocation('nonexistent', { name: 'Nope' });
+		expect(result).toBeUndefined();
+	});
+
+	it('does not modify fields that are not in the updates', async () => {
+		await createLocation(
+			makeLocation({ id: 'upd-loc4', name: 'Room', locationType: 'room' })
+		);
+		await updateLocation('upd-loc4', { name: 'Updated Room' });
+		const fetched = await getLocationById('upd-loc4');
+		expect(fetched!.name).toBe('Updated Room');
+		expect(fetched!.locationType).toBe('room');
+	});
+});
+
+describe('removeLocation', () => {
+	it('deletes a location from the database', async () => {
+		await createLocation(makeLocation({ id: 'del-loc' }));
+		await removeLocation('del-loc');
+		const result = await getLocationById('del-loc');
+		expect(result).toBeUndefined();
+	});
+
+	it('does not throw when removing a non-existent location', async () => {
+		await expect(removeLocation('nonexistent')).resolves.toBeUndefined();
+	});
+
+	it('only removes the specified location', async () => {
+		await createLocation(makeLocation({ id: 'keep-loc' }));
+		await createLocation(makeLocation({ id: 'del-loc2' }));
+		await removeLocation('del-loc2');
+		const all = await getAllLocations();
+		expect(all).toHaveLength(1);
+		expect(all[0].id).toBe('keep-loc');
+	});
+});
+
+describe('getLocationsByParent', () => {
+	it('returns children of a given parent', async () => {
+		await createLocation(makeLocation({ id: 'house', name: 'House', parentId: null }));
+		await createLocation(
+			makeLocation({ id: 'floor1', name: 'Floor 1', parentId: 'house' })
+		);
+		await createLocation(
+			makeLocation({ id: 'floor2', name: 'Floor 2', parentId: 'house' })
+		);
+		await createLocation(
+			makeLocation({ id: 'room1', name: 'Room 1', parentId: 'floor1' })
+		);
+
+		const houseChildren = await getLocationsByParent('house');
+		expect(houseChildren).toHaveLength(2);
+		const childIds = houseChildren.map((l) => l.id);
+		expect(childIds).toContain('floor1');
+		expect(childIds).toContain('floor2');
+	});
+
+	it('returns an empty array when no children exist', async () => {
+		await createLocation(makeLocation({ id: 'leaf', parentId: null }));
+		const children = await getLocationsByParent('leaf');
+		expect(children).toEqual([]);
+	});
+});
+
+describe('seedDefaultLocations', () => {
+	it('populates default locations when the store is empty', async () => {
+		await seedDefaultLocations();
+		const all = await getAllLocations();
+		expect(all.length).toBe(11);
+	});
+
+	it('includes expected default locations', async () => {
+		await seedDefaultLocations();
+		const home = await getLocationById('home');
+		expect(home).toBeDefined();
+		expect(home!.name).toBe('Home');
+		expect(home!.locationType).toBe('house');
+
+		const kueche = await getLocationById('kueche');
+		expect(kueche).toBeDefined();
+		expect(kueche!.name).toBe('Küche');
+		expect(kueche!.parentId).toBe('eg');
+	});
+
+	it('sets createdAt and updatedAt on seeded locations', async () => {
+		await seedDefaultLocations();
+		const home = await getLocationById('home');
+		expect(home!.createdAt).toBeDefined();
+		expect(home!.updatedAt).toBeDefined();
+		expect(() => new Date(home!.createdAt)).not.toThrow();
+	});
+
+	it('skips seeding when locations already exist', async () => {
+		await createLocation(makeLocation({ id: 'custom', name: 'Custom Location' }));
+		await seedDefaultLocations();
+		const all = await getAllLocations();
+		// Should only have the one custom location, not 11 defaults + 1 custom
+		expect(all).toHaveLength(1);
+		expect(all[0].id).toBe('custom');
+	});
+
+	it('is idempotent — calling twice does not duplicate data', async () => {
+		await seedDefaultLocations();
+		await seedDefaultLocations();
+		const all = await getAllLocations();
+		expect(all).toHaveLength(11);
+	});
+});
diff --git a/src/lib/data/locations.ts b/src/lib/data/locations.ts
new file mode 100644
index 0000000..c3b880f
--- /dev/null
+++ b/src/lib/data/locations.ts
@@ -0,0 +1,64 @@
+import { getDB } from './db';
+import type { Location } from '$lib/types';
+
+export async function getAllLocations(): Promise<Location[]> {
+	const db = await getDB();
+	return db.getAll('locations');
+}
+
+export async function getLocationById(id: string): Promise<Location | undefined> {
+	const db = await getDB();
+	return db.get('locations', id);
+}
+
+export async function createLocation(location: Location): Promise<Location> {
+	const db = await getDB();
+	await db.put('locations', location);
+	return location;
+}
+
+export async function updateLocation(id: string, updates: Partial<Location>): Promise<Location | undefined> {
+	const db = await getDB();
+	const existing = await db.get('locations', id);
+	if (!existing) return undefined;
+	const updated = { ...existing, ...updates, updatedAt: new Date().toISOString() };
+	await db.put('locations', updated);
+	return updated;
+}
+
+export async function removeLocation(id: string): Promise<void> {
+	const db = await getDB();
+	await db.delete('locations', id);
+}
+
+export async function getLocationsByParent(parentId: string | null): Promise<Location[]> {
+	const db = await getDB();
+	return db.getAllFromIndex('locations', 'by-parent', parentId as string);
+}
+
+const DEFAULT_LOCATIONS: Omit<Location, 'createdAt' | 'updatedAt'>[] = [
+	{ id: 'home', name: 'Home', description: '', parentId: null, locationType: 'house', defaultStorageTier: null, sortOrder: 0 },
+	{ id: 'eg', name: 'Erdgeschoss', description: '', parentId: 'home', locationType: 'floor', defaultStorageTier: null, sortOrder: 0 },
+	{ id: 'og', name: 'Obergeschoss', description: '', parentId: 'home', locationType: 'floor', defaultStorageTier: null, sortOrder: 1 },
+	{ id: 'keller', name: 'Keller', description: '', parentId: 'home', locationType: 'floor', defaultStorageTier: null, sortOrder: 2 },
+	{ id: 'kueche', name: 'Küche', description: '', parentId: 'eg', locationType: 'room', defaultStorageTier: null, sortOrder: 0 },
+	{ id: 'wohnzimmer', name: 'Wohnzimmer', description: '', parentId: 'eg', locationType: 'room', defaultStorageTier: null, sortOrder: 1 },
+	{ id: 'flur', name: 'Flur', description: '', parentId: 'eg', locationType: 'room', defaultStorageTier: null, sortOrder: 2 },
+	{ id: 'schlafzimmer', name: 'Schlafzimmer', description: '', parentId: 'og', locationType: 'room', defaultStorageTier: null, sortOrder: 0 },
+	{ id: 'buero', name: 'Büro', description: '', parentId: 'og', locationType: 'room', defaultStorageTier: null, sortOrder: 1 },
+	{ id: 'bad', name: 'Bad', description: '', parentId: 'og', locationType: 'room', defaultStorageTier: null, sortOrder: 2 },
+	{ id: 'werkstatt', name: 'Werkstatt', description: '', parentId: 'keller', locationType: 'room', defaultStorageTier: null, sortOrder: 0 },
+];
+
+export async function seedDefaultLocations(): Promise<void> {
+	const db = await getDB();
+	const existing = await db.count('locations');
+	if (existing > 0) return;
+
+	const now = new Date().toISOString();
+	const tx = db.transaction('locations', 'readwrite');
+	for (const loc of DEFAULT_LOCATIONS) {
+		await tx.store.put({ ...loc, createdAt: now, updatedAt: now });
+	}
+	await tx.done;
+}
diff --git a/src/lib/data/sightings.test.ts b/src/lib/data/sightings.test.ts
new file mode 100644
index 0000000..73549b8
--- /dev/null
+++ b/src/lib/data/sightings.test.ts
@@ -0,0 +1,151 @@
+import { describe, it, expect, beforeEach } from 'vitest';
+import { deleteDB } from 'idb';
+import { resetDBPromise } from '$lib/data/db';
+import {
+	createSighting,
+	getSightingsByItem,
+	getSightingsByLocation,
+	getAllSightings,
+	removeSighting,
+} from '$lib/data/sightings';
+import type { Sighting } from '$lib/types';
+
+function makeSighting(overrides: Partial<Sighting> = {}): Sighting {
+	return {
+		id: 's_test001',
+		itemId: 'abc1234',
+		locationId: 'kueche',
+		timestamp: new Date().toISOString(),
+		sightingType: 'scan',
+		confidence: 'confirmed',
+		notes: '',
+		createdBy: null,
+		...overrides,
+	};
+}
+
+beforeEach(async () => {
+	await resetDBPromise();
+	await deleteDB('solidhaus');
+});
+
+describe('createSighting', () => {
+	it('creates a sighting and returns it', async () => {
+		const sighting = makeSighting();
+		const result = await createSighting(sighting);
+		expect(result).toEqual(sighting);
+	});
+
+	it('persists the sighting in the database', async () => {
+		const sighting = makeSighting({ id: 's_persist' });
+		await createSighting(sighting);
+		const all = await getAllSightings();
+		expect(all).toHaveLength(1);
+		expect(all[0].id).toBe('s_persist');
+	});
+
+	it('creates multiple sightings', async () => {
+		await createSighting(makeSighting({ id: 's_one' }));
+		await createSighting(makeSighting({ id: 's_two' }));
+		await createSighting(makeSighting({ id: 's_three' }));
+		const all = await getAllSightings();
+		expect(all).toHaveLength(3);
+	});
+
+	it('stores all sighting fields correctly', async () => {
+		const sighting = makeSighting({
+			id: 's_full',
+			itemId: 'item777',
+			locationId: 'buero',
+			sightingType: 'manual',
+			confidence: 'inferred',
+			notes: 'Spotted on desk',
+			createdBy: 'user-42',
+		});
+		await createSighting(sighting);
+		const all = await getAllSightings();
+		const stored = all.find((s) => s.id === 's_full');
+		expect(stored).toBeDefined();
+		expect(stored!.itemId).toBe('item777');
+		expect(stored!.locationId).toBe('buero');
+		expect(stored!.sightingType).toBe('manual');
+		expect(stored!.confidence).toBe('inferred');
+		expect(stored!.notes).toBe('Spotted on desk');
+		expect(stored!.createdBy).toBe('user-42');
+	});
+});
+
+describe('getSightingsByItem', () => {
+	it('returns sightings for a specific item', async () => {
+		await createSighting(makeSighting({ id: 's_a1', itemId: 'item-a' }));
+		await createSighting(makeSighting({ id: 's_a2', itemId: 'item-a' }));
+		await createSighting(makeSighting({ id: 's_b1', itemId: 'item-b' }));
+
+		const sightings = await getSightingsByItem('item-a');
+		expect(sightings).toHaveLength(2);
+		expect(sightings.every((s) => s.itemId === 'item-a')).toBe(true);
+	});
+
+	it('returns an empty array when no sightings exist for the item', async () => {
+		await createSighting(makeSighting({ id: 's_other', itemId: 'item-x' }));
+		const sightings = await getSightingsByItem('item-y');
+		expect(sightings).toEqual([]);
+	});
+
+	it('returns an empty array when the database is empty', async () => {
+		const sightings = await getSightingsByItem('anything');
+		expect(sightings).toEqual([]);
+	});
+});
+
+describe('getSightingsByLocation', () => {
+	it('returns sightings for a specific location', async () => {
+		await createSighting(makeSighting({ id: 's_k1', locationId: 'kueche' }));
+		await createSighting(makeSighting({ id: 's_k2', locationId: 'kueche' }));
+		await createSighting(makeSighting({ id: 's_b1', locationId: 'buero' }));
+
+		const sightings = await getSightingsByLocation('kueche');
+		expect(sightings).toHaveLength(2);
+		expect(sightings.every((s) => s.locationId === 'kueche')).toBe(true);
+	});
+
+	it('returns an empty array when no sightings exist for the location', async () => {
+		await createSighting(makeSighting({ id: 's_elsewhere', locationId: 'werkstatt' }));
+		const sightings = await getSightingsByLocation('schlafzimmer');
+		expect(sightings).toEqual([]);
+	});
+
+	it('returns an empty array when the database is empty', async () => {
+		const sightings = await getSightingsByLocation('anywhere');
+		expect(sightings).toEqual([]);
+	});
+});
+
+describe('removeSighting', () => {
+	it('deletes a sighting from the database', async () => {
+		await createSighting(makeSighting({ id: 's_del' }));
+		await removeSighting('s_del');
+		const all = await getAllSightings();
+		expect(all).toHaveLength(0);
+	});
+
+	it('does not throw when removing a non-existent sighting', async () => {
+		await expect(removeSighting('s_nonexistent')).resolves.toBeUndefined();
+	});
+
+	it('only removes the specified sighting', async () => {
+		await createSighting(makeSighting({ id: 's_keep' }));
+		await createSighting(makeSighting({ id: 's_remove' }));
+		await removeSighting('s_remove');
+		const all = await getAllSightings();
+		expect(all).toHaveLength(1);
+		expect(all[0].id).toBe('s_keep');
+	});
+});
+
+describe('getAllSightings', () => {
+	it('returns an empty array when no sightings exist', async () => {
+		const all = await getAllSightings();
+		expect(all).toEqual([]);
+	});
+});
diff --git a/src/lib/data/sightings.ts b/src/lib/data/sightings.ts
new file mode 100644
index 0000000..d533529
--- /dev/null
+++ b/src/lib/data/sightings.ts
@@ -0,0 +1,28 @@
+import { getDB } from './db';
+import type { Sighting } from '$lib/types';
+
+export async function createSighting(sighting: Sighting): Promise<Sighting> {
+	const db = await getDB();
+	await db.put('sightings', sighting);
+	return sighting;
+}
+
+export async function getSightingsByItem(itemId: string): Promise<Sighting[]> {
+	const db = await getDB();
+	return db.getAllFromIndex('sightings', 'by-item', itemId);
+}
+
+export async function getSightingsByLocation(locationId: string): Promise<Sighting[]> {
+	const db = await getDB();
+	return db.getAllFromIndex('sightings', 'by-location', locationId);
+}
+
+export async function getAllSightings(): Promise<Sighting[]> {
+	const db = await getDB();
+	return db.getAll('sightings');
+}
+
+export async function removeSighting(id: string): Promise<void> {
+	const db = await getDB();
+	await db.delete('sightings', id);
+}
diff --git a/src/lib/scanning/parser.test.ts b/src/lib/scanning/parser.test.ts
new file mode 100644
index 0000000..706cef8
--- /dev/null
+++ b/src/lib/scanning/parser.test.ts
@@ -0,0 +1,150 @@
+import { describe, it, expect } from 'vitest';
+import { parseItemId } from '$lib/scanning/parser';
+import { generateItemId, generateSightingId } from '$lib/utils/id';
+
+describe('parseItemId', () => {
+	describe('HTTPS URI format', () => {
+		it('parses a valid HTTPS URI', () => {
+			expect(parseItemId('https://haus.toph.so/abc2345')).toBe('abc2345');
+		});
+
+		it('parses a valid HTTPS URI with different valid ID', () => {
+			expect(parseItemId('https://haus.toph.so/mn3pqr7')).toBe('mn3pqr7');
+		});
+
+		it('returns null for HTTPS URI with invalid characters in ID', () => {
+			expect(parseItemId('https://haus.toph.so/abc1lO0')).toBeNull();
+		});
+
+		it('returns null for HTTPS URI with wrong length ID', () => {
+			expect(parseItemId('https://haus.toph.so/abc23')).toBeNull();
+		});
+
+		it('returns null for wrong domain', () => {
+			expect(parseItemId('https://example.com/abc2345')).toBeNull();
+		});
+	});
+
+	describe('custom scheme format', () => {
+		it('parses a valid haus:// URI', () => {
+			expect(parseItemId('haus://abc2345')).toBe('abc2345');
+		});
+
+		it('returns null for haus:// URI with invalid characters', () => {
+			expect(parseItemId('haus://abc1lO0')).toBeNull();
+		});
+
+		it('returns null for haus:// URI with wrong length', () => {
+			expect(parseItemId('haus://abc23456789')).toBeNull();
+		});
+	});
+
+	describe('raw ID format', () => {
+		it('parses a valid raw 7-char ID', () => {
+			expect(parseItemId('abc2345')).toBe('abc2345');
+		});
+
+		it('accepts all valid alphabet characters', () => {
+			// Alphabet: 23456789abcdefghjkmnpqrstuvwxyz
+			expect(parseItemId('2345678')).toBe('2345678');
+			expect(parseItemId('abcdefg')).toBe('abcdefg');
+			expect(parseItemId('hjkmnpq')).toBe('hjkmnpq');
+			expect(parseItemId('rstuvwx')).toBe('rstuvwx');
+		});
+
+		it('rejects excluded characters (0, 1, i, l, o)', () => {
+			expect(parseItemId('abc0def')).toBeNull();
+			expect(parseItemId('abc1def')).toBeNull();
+			expect(parseItemId('abcidef')).toBeNull();
+			expect(parseItemId('abcldef')).toBeNull();
+			expect(parseItemId('abcodef')).toBeNull();
+		});
+
+		it('rejects uppercase characters', () => {
+			expect(parseItemId('ABCdefg')).toBeNull();
+		});
+	});
+
+	describe('invalid inputs', () => {
+		it('returns null for empty string', () => {
+			expect(parseItemId('')).toBeNull();
+		});
+
+		it('returns null for wrong length (too short)', () => {
+			expect(parseItemId('abc23')).toBeNull();
+		});
+
+		it('returns null for wrong length (too long)', () => {
+			expect(parseItemId('abc23456')).toBeNull();
+		});
+
+		it('returns null for string with spaces', () => {
+			expect(parseItemId('abc 234')).toBeNull();
+		});
+
+		it('returns null for string with special characters', () => {
+			expect(parseItemId('abc-234')).toBeNull();
+		});
+
+		it('returns null for completely invalid input', () => {
+			expect(parseItemId('not a barcode at all')).toBeNull();
+		});
+	});
+});
+
+describe('generateItemId', () => {
+	const VALID_CHARS = /^[23456789a-hjkmnp-z]+$/;
+
+	it('generates a 7-character string', () => {
+		const id = generateItemId();
+		expect(id).toHaveLength(7);
+	});
+
+	it('uses only valid alphabet characters', () => {
+		for (let i = 0; i < 50; i++) {
+			const id = generateItemId();
+			expect(id).toMatch(VALID_CHARS);
+		}
+	});
+
+	it('does not contain ambiguous characters (0, 1, i, l, o)', () => {
+		for (let i = 0; i < 50; i++) {
+			const id = generateItemId();
+			expect(id).not.toMatch(/[01ilo]/);
+		}
+	});
+
+	it('generates unique IDs across multiple calls', () => {
+		const ids = new Set<string>();
+		for (let i = 0; i < 1000; i++) {
+			ids.add(generateItemId());
+		}
+		expect(ids.size).toBe(1000);
+	});
+});
+
+describe('generateSightingId', () => {
+	it('starts with "s_" prefix', () => {
+		const id = generateSightingId();
+		expect(id.startsWith('s_')).toBe(true);
+	});
+
+	it('has total length of 9 (2 prefix + 7 ID)', () => {
+		const id = generateSightingId();
+		expect(id).toHaveLength(9);
+	});
+
+	it('has a valid item ID after the prefix', () => {
+		const id = generateSightingId();
+		const suffix = id.slice(2);
+		expect(suffix).toMatch(/^[23456789a-hjkmnp-z]{7}$/);
+	});
+
+	it('generates unique IDs across multiple calls', () => {
+		const ids = new Set<string>();
+		for (let i = 0; i < 100; i++) {
+			ids.add(generateSightingId());
+		}
+		expect(ids.size).toBe(100);
+	});
+});
diff --git a/src/lib/scanning/parser.ts b/src/lib/scanning/parser.ts
new file mode 100644
index 0000000..dc8b9cf
--- /dev/null
+++ b/src/lib/scanning/parser.ts
@@ -0,0 +1,18 @@
+const VALID_CHARS = /^[23456789a-hjkmnp-z]{7}$/;
+
+export function parseItemId(rawValue: string): string | null {
+	if (!rawValue) return null;
+
+	// HTTPS URI
+	const httpsMatch = rawValue.match(/haus\.toph\.so\/([23456789a-hjkmnp-z]{7})\/?$/);
+	if (httpsMatch) return httpsMatch[1];
+
+	// Custom scheme
+	const schemeMatch = rawValue.match(/^haus:\/\/([23456789a-hjkmnp-z]{7})$/);
+	if (schemeMatch) return schemeMatch[1];
+
+	// Raw ID
+	if (VALID_CHARS.test(rawValue)) return rawValue;
+
+	return null;
+}
diff --git a/src/lib/utils/confidence.test.ts b/src/lib/utils/confidence.test.ts
new file mode 100644
index 0000000..56adb06
--- /dev/null
+++ b/src/lib/utils/confidence.test.ts
@@ -0,0 +1,50 @@
+import { describe, it, expect } from 'vitest';
+import { getConfidence } from '$lib/utils/confidence';
+
+function daysAgo(days: number): string {
+	const date = new Date();
+	date.setDate(date.getDate() - days);
+	return date.toISOString();
+}
+
+describe('getConfidence', () => {
+	it('returns "unknown" when lastSeenTimestamp is null', () => {
+		expect(getConfidence(null)).toBe('unknown');
+	});
+
+	it('returns "confirmed" for a timestamp from today', () => {
+		expect(getConfidence(new Date().toISOString())).toBe('confirmed');
+	});
+
+	it('returns "confirmed" at the 30-day boundary', () => {
+		expect(getConfidence(daysAgo(30))).toBe('confirmed');
+	});
+
+	it('returns "likely" at 31 days ago', () => {
+		expect(getConfidence(daysAgo(31))).toBe('likely');
+	});
+
+	it('returns "likely" at the 90-day boundary', () => {
+		expect(getConfidence(daysAgo(90))).toBe('likely');
+	});
+
+	it('returns "assumed" at 91 days ago', () => {
+		expect(getConfidence(daysAgo(91))).toBe('assumed');
+	});
+
+	it('returns "assumed" at the 180-day boundary', () => {
+		expect(getConfidence(daysAgo(180))).toBe('assumed');
+	});
+
+	it('returns "unknown" at 181 days ago', () => {
+		expect(getConfidence(daysAgo(181))).toBe('unknown');
+	});
+
+	it('returns "unknown" for a very old timestamp', () => {
+		expect(getConfidence('2020-01-01T00:00:00.000Z')).toBe('unknown');
+	});
+
+	it('returns "confirmed" for a timestamp 1 day ago', () => {
+		expect(getConfidence(daysAgo(1))).toBe('confirmed');
+	});
+});
diff --git a/src/lib/utils/confidence.ts b/src/lib/utils/confidence.ts
new file mode 100644
index 0000000..3a672d2
--- /dev/null
+++ b/src/lib/utils/confidence.ts
@@ -0,0 +1,15 @@
+import { differenceInDays } from 'date-fns';
+import type { LocationConfidence } from '$lib/types';
+
+export function getConfidence(lastSeenTimestamp: string | null): LocationConfidence {
+	if (!lastSeenTimestamp) return 'unknown';
+
+	const date = new Date(lastSeenTimestamp);
+	if (isNaN(date.getTime())) return 'unknown';
+
+	const daysSince = differenceInDays(new Date(), date);
+	if (daysSince <= 30) return 'confirmed';
+	if (daysSince <= 90) return 'likely';
+	if (daysSince <= 180) return 'assumed';
+	return 'unknown';
+}
diff --git a/src/lib/utils/custody.test.ts b/src/lib/utils/custody.test.ts
new file mode 100644
index 0000000..5316dfa
--- /dev/null
+++ b/src/lib/utils/custody.test.ts
@@ -0,0 +1,138 @@
+import { describe, it, expect } from 'vitest';
+import { buildCheckOutUpdate, buildCheckInUpdate } from '$lib/utils/custody';
+
+describe('buildCheckOutUpdate', () => {
+	it('returns custodyState "checked-out"', () => {
+		const result = buildCheckOutUpdate('in-use', 'loc-from', 'loc-to');
+		expect(result.custodyState).toBe('checked-out');
+	});
+
+	it('sets checkedOutSince to a valid ISO timestamp', () => {
+		const before = new Date().toISOString();
+		const result = buildCheckOutUpdate('in-use', 'loc-from', 'loc-to');
+		const after = new Date().toISOString();
+
+		expect(result.checkedOutSince).toBeDefined();
+		expect(result.checkedOutSince! >= before).toBe(true);
+		expect(result.checkedOutSince! <= after).toBe(true);
+	});
+
+	it('sets the checkout reason', () => {
+		const result = buildCheckOutUpdate('lent', 'loc-from', 'loc-to');
+		expect(result.checkedOutReason).toBe('lent');
+	});
+
+	it('sets checkedOutFrom to the from location', () => {
+		const result = buildCheckOutUpdate('in-use', 'kitchen', 'garage');
+		expect(result.checkedOutFrom).toBe('kitchen');
+	});
+
+	it('sets checkedOutTo to the to location', () => {
+		const result = buildCheckOutUpdate('in-use', 'kitchen', 'garage');
+		expect(result.checkedOutTo).toBe('garage');
+	});
+
+	it('sets checkedOutNote when provided', () => {
+		const result = buildCheckOutUpdate('lent', 'loc-a', 'loc-b', 'Lent to neighbor');
+		expect(result.checkedOutNote).toBe('Lent to neighbor');
+	});
+
+	it('sets checkedOutNote to empty string or null when not provided', () => {
+		const result = buildCheckOutUpdate('in-use', 'loc-a', 'loc-b');
+		// Accept either null, undefined, or empty string as "no note"
+		expect(result.checkedOutNote === null || result.checkedOutNote === undefined || result.checkedOutNote === '').toBe(true);
+	});
+
+	it('sets lastSeenAt to toLocationId when provided', () => {
+		const result = buildCheckOutUpdate('in-transit', 'loc-a', 'loc-b');
+		expect(result.lastSeenAt).toBe('loc-b');
+	});
+
+	it('sets lastSeenAt to fromLocationId when toLocationId is null', () => {
+		const result = buildCheckOutUpdate('in-use', 'loc-a', null);
+		expect(result.lastSeenAt).toBe('loc-a');
+	});
+
+	it('sets lastSeenAt to fromLocationId when toLocationId is empty string', () => {
+		const result = buildCheckOutUpdate('in-use', 'loc-a', '');
+		expect(result.lastSeenAt).toBe('loc-a');
+	});
+
+	it('sets locationConfidence to "confirmed"', () => {
+		const result = buildCheckOutUpdate('in-use', 'loc-a', 'loc-b');
+		expect(result.locationConfidence).toBe('confirmed');
+	});
+
+	it('sets lastSeenTimestamp', () => {
+		const result = buildCheckOutUpdate('in-use', 'loc-a', 'loc-b');
+		expect(result.lastSeenTimestamp).toBeDefined();
+		// Should be a valid ISO string
+		expect(new Date(result.lastSeenTimestamp!).toISOString()).toBe(result.lastSeenTimestamp);
+	});
+
+	it('handles all checkout reason types', () => {
+		const reasons = ['in-use', 'in-transit', 'lent', 'in-repair', 'temporary', 'consumed'] as const;
+		for (const reason of reasons) {
+			const result = buildCheckOutUpdate(reason, 'loc-a', 'loc-b');
+			expect(result.checkedOutReason).toBe(reason);
+			expect(result.custodyState).toBe('checked-out');
+		}
+	});
+});
+
+describe('buildCheckInUpdate', () => {
+	it('returns custodyState "checked-in"', () => {
+		const result = buildCheckInUpdate('living-room');
+		expect(result.custodyState).toBe('checked-in');
+	});
+
+	it('nulls checkedOutSince', () => {
+		const result = buildCheckInUpdate('living-room');
+		expect(result.checkedOutSince).toBeNull();
+	});
+
+	it('nulls checkedOutReason', () => {
+		const result = buildCheckInUpdate('living-room');
+		expect(result.checkedOutReason).toBeNull();
+	});
+
+	it('nulls checkedOutFrom', () => {
+		const result = buildCheckInUpdate('living-room');
+		expect(result.checkedOutFrom).toBeNull();
+	});
+
+	it('nulls checkedOutTo', () => {
+		const result = buildCheckInUpdate('living-room');
+		expect(result.checkedOutTo).toBeNull();
+	});
+
+	it('nulls checkedOutNote', () => {
+		const result = buildCheckInUpdate('living-room');
+		expect(result.checkedOutNote).toBeNull();
+	});
+
+	it('sets lastSeenAt to the return location', () => {
+		const result = buildCheckInUpdate('kitchen');
+		expect(result.lastSeenAt).toBe('kitchen');
+	});
+
+	it('sets supposedToBeAt to the return location', () => {
+		const result = buildCheckInUpdate('kitchen');
+		expect(result.supposedToBeAt).toBe('kitchen');
+	});
+
+	it('sets locationConfidence to "confirmed"', () => {
+		const result = buildCheckInUpdate('kitchen');
+		expect(result.locationConfidence).toBe('confirmed');
+	});
+
+	it('sets lastSeenTimestamp to a valid ISO timestamp', () => {
+		const before = new Date().toISOString();
+		const result = buildCheckInUpdate('kitchen');
+		const after = new Date().toISOString();
+
+		expect(result.lastSeenTimestamp).toBeDefined();
+		expect(result.lastSeenTimestamp! >= before).toBe(true);
+		expect(result.lastSeenTimestamp! <= after).toBe(true);
+	});
+});
diff --git a/src/lib/utils/custody.ts b/src/lib/utils/custody.ts
new file mode 100644
index 0000000..85a8dd2
--- /dev/null
+++ b/src/lib/utils/custody.ts
@@ -0,0 +1,37 @@
+import type { Item, CheckOutReason } from '$lib/types';
+
+export function buildCheckOutUpdate(
+	reason: CheckOutReason,
+	fromLocationId: string,
+	toLocationId: string | null,
+	note: string = '',
+): Partial<Item> {
+	const now = new Date().toISOString();
+	return {
+		custodyState: 'checked-out',
+		checkedOutSince: now,
+		checkedOutReason: reason,
+		checkedOutFrom: fromLocationId,
+		checkedOutTo: toLocationId,
+		checkedOutNote: note,
+		lastSeenAt: toLocationId || fromLocationId,
+		lastSeenTimestamp: now,
+		locationConfidence: 'confirmed',
+	};
+}
+
+export function buildCheckInUpdate(returnToLocationId: string): Partial<Item> {
+	const now = new Date().toISOString();
+	return {
+		custodyState: 'checked-in',
+		checkedOutSince: null,
+		checkedOutReason: null,
+		checkedOutFrom: null,
+		checkedOutTo: null,
+		checkedOutNote: null,
+		lastSeenAt: returnToLocationId,
+		lastSeenTimestamp: now,
+		locationConfidence: 'confirmed',
+		supposedToBeAt: returnToLocationId,
+	};
+}