diff --git a/src/db.js b/src/db.js
new file mode 100644
index 0000000..d771c31
--- /dev/null
+++ b/src/db.js
@@ -0,0 +1,58 @@
+const Database = require('better-sqlite3');
+const fs = require('node:fs');
+const path = require('node:path');
+
+const SCHEMA = `
+CREATE TABLE IF NOT EXISTS products (
+  id INTEGER PRIMARY KEY AUTOINCREMENT,
+  name TEXT NOT NULL,
+  url TEXT NOT NULL,
+  last_price REAL,
+  last_checked_at TEXT,
+  last_check_status TEXT,
+  created_at TEXT NOT NULL
+)`;
+
+function openDb(dbPath) {
+  if (dbPath !== ':memory:') {
+    fs.mkdirSync(path.dirname(dbPath), { recursive: true });
+  }
+  const db = new Database(dbPath);
+  db.exec(SCHEMA);
+  return db;
+}
+
+function listProducts(db) {
+  return db.prepare('SELECT * FROM products ORDER BY created_at ASC').all();
+}
+
+function getProduct(db, id) {
+  return db.prepare('SELECT * FROM products WHERE id = ?').get(id);
+}
+
+function addProduct(db, { name, url }) {
+  const createdAt = new Date().toISOString();
+  const info = db.prepare(
+    'INSERT INTO products (name, url, created_at) VALUES (?, ?, ?)'
+  ).run(name, url, createdAt);
+  return getProduct(db, info.lastInsertRowid);
+}
+
+function deleteProduct(db, id) {
+  db.prepare('DELETE FROM products WHERE id = ?').run(id);
+}
+
+function recordCheckSuccess(db, id, { price, checkedAt }) {
+  db.prepare(
+    'UPDATE products SET last_price = ?, last_checked_at = ?, last_check_status = ? WHERE id = ?'
+  ).run(price, checkedAt, 'ok', id);
+}
+
+function recordCheckFailure(db, id, status) {
+  db.prepare('UPDATE products SET last_check_status = ? WHERE id = ?').run(status, id);
+}
+
+module.exports = {
+  openDb, listProducts, getProduct, addProduct, deleteProduct,
+  recordCheckSuccess, recordCheckFailure,
+};
diff --git a/test/db.test.js b/test/db.test.js
new file mode 100644
index 0000000..f463dca
--- /dev/null
+++ b/test/db.test.js
@@ -0,0 +1,64 @@
+const test = require('node:test');
+const assert = require('node:assert/strict');
+const {
+  openDb, listProducts, getProduct, addProduct, deleteProduct,
+  recordCheckSuccess, recordCheckFailure,
+} = require('../src/db');
+
+function freshDb() {
+  return openDb(':memory:');
+}
+
+test('addProduct inserts a row with defaults and returns it', () => {
+  const db = freshDb();
+  const product = addProduct(db, { name: 'Voorbeeld', url: 'https://example.com' });
+  assert.equal(product.name, 'Voorbeeld');
+  assert.equal(product.url, 'https://example.com');
+  assert.equal(product.last_price, null);
+  assert.equal(product.last_checked_at, null);
+  assert.ok(product.created_at);
+  assert.ok(product.id);
+});
+
+test('listProducts returns all inserted products in insertion order', () => {
+  const db = freshDb();
+  addProduct(db, { name: 'A', url: 'https://a' });
+  addProduct(db, { name: 'B', url: 'https://b' });
+  const products = listProducts(db);
+  assert.equal(products.length, 2);
+  assert.equal(products[0].name, 'A');
+  assert.equal(products[1].name, 'B');
+});
+
+test('getProduct returns undefined for an unknown id', () => {
+  const db = freshDb();
+  assert.equal(getProduct(db, 999), undefined);
+});
+
+test('deleteProduct removes the row', () => {
+  const db = freshDb();
+  const product = addProduct(db, { name: 'A', url: 'https://a' });
+  deleteProduct(db, product.id);
+  assert.equal(getProduct(db, product.id), undefined);
+});
+
+test('recordCheckSuccess updates price, timestamp and status', () => {
+  const db = freshDb();
+  const product = addProduct(db, { name: 'A', url: 'https://a' });
+  recordCheckSuccess(db, product.id, { price: 12.5, checkedAt: '2026-09-05T08:00:00.000Z' });
+  const updated = getProduct(db, product.id);
+  assert.equal(updated.last_price, 12.5);
+  assert.equal(updated.last_checked_at, '2026-09-05T08:00:00.000Z');
+  assert.equal(updated.last_check_status, 'ok');
+});
+
+test('recordCheckFailure only updates the status, leaving price and timestamp untouched', () => {
+  const db = freshDb();
+  const product = addProduct(db, { name: 'A', url: 'https://a' });
+  recordCheckSuccess(db, product.id, { price: 12.5, checkedAt: '2026-09-05T08:00:00.000Z' });
+  recordCheckFailure(db, product.id, 'fetch_error');
+  const updated = getProduct(db, product.id);
+  assert.equal(updated.last_price, 12.5);
+  assert.equal(updated.last_checked_at, '2026-09-05T08:00:00.000Z');
+  assert.equal(updated.last_check_status, 'fetch_error');
+});