A barcode is an identifier, not an inventory count
The black bars do not contain your current quantity or sale history. They normally identify a code that your catalog maps to a product. The inventory system still needs the quantity, unit, location and operation that explains a change.
This separation is useful. A scan can quickly find the item while the user remains responsible for confirming whether the event is a sale, purchase, transfer or count adjustment.
When a phone camera is enough
For a small shop, reseller or event vendor with moderate scan volume, the phone already in hand may be the simplest starting point. Dedicated scanners can be faster for high-throughput warehouses, damaged labels and long scanning sessions.
Test more than one perfect package. Include glossy wrappers, small labels, curved surfaces and older printing. The camera needs adequate focus and light.
Prevent duplicate or ambiguous codes
Each scannable code should map to the intended product. Reusing one code for several items makes the fastest scanner unreliable. When a scan gives no match, verify the digits before creating a new product so that a formatting difference does not produce a duplicate.
Build a safe sales test
Create a product with quantity 10, scan it into a sale, enter quantity 2 and complete the operation. Confirm that the intended location now shows 8 and that the movement history records the sale. Then cancel the transaction and inspect the reversal. This tests the whole business workflow, not just the camera animation.