This tag is used for questions that involve software that scans or interprets barcodes or interfaces with barcode readers. Information needed in postings with this tag includes the type of barcode involved (1D, 2D), barcode type or standard (UPC-A, GS1 Databar, QR Code, etc.), and the barcode application (package tracking, retail sales, etc.) plus the reader hardware involved (dedicated reader, smartphone w/ OS).

Wikipedia defines a barcode as "an optical, machine-readable, representation of data; the data usually describes something about the object that carries the barcode". The most common barcodes are the standard 1D vertical bars type of barcode on grocery store items, coupons, and tracking labels. Other barcodes such as the 2D QR Code have seen some use in applications. One application of the QR Code is to contain a web site URL which allows a person with a camera equipped smartphone with the proper software to read the QR Code and navigate to the URL embedded in the barcode.

Barcodes provide a way to store information in a symbol. Different barcode standards allow for different kinds and amounts of information. Some barcode standards allow for numeric digits only while others allow alphanumeric characters.

One common use of barcodes is in grocery stores in which each type of item has an identifying code as a barcode which identifies the stock inventory identifier of the item type. The barcode allows for computers to identify the item by scanning the barcode and then looking up the identifier embedded in the barcode to determine pricing information as well as to automatically handle inventory.

A second common use is to uniquely identify containers or packages so that a package or container can be tracked as it moves through a logistical chain from location to location as it is shipped from its source to its destination.

Barcode readers come in a variety of styles and technologies. The standard laser type of scanning reader, normally used with 1D barcodes, may be built into a counter or may be a hand held scanners. These scanners read the barcode by using a laser to move across the barcode allowing the device to read it. Other kinds of barcode readers process the image from a camera in order to read the barcode.