GS1 Application Identifiers you'll actually use

Updated July 2026

GS1 defines well over a hundred Application Identifiers. For a retail 2D migration you will use about six.

AI	Meaning	Format	Where it goes in a Digital Link
01	GTIN	14 digits	Path — the primary key
22	Consumer product variant	up to 20 chars	Path qualifier, first
10	Batch / lot	up to 20 chars	Path qualifier, second
21	Serial number	up to 20 chars	Path qualifier, third
17	Expiration date	YYMMDD	Query string
15	Best before date	YYMMDD	Query string

The ordering rule

Path qualifiers must appear in the order 22 → 10 → 21. Not the order you find convenient, and not the numeric order. A URL like /01/00036000291452/21/SN1/10/LOT1 is malformed even though every individual part is valid — and while your own resolver may accept it, other trading partners' systems will not.

Dates and the end-of-month convention

Dates are YYMMDD. A day of 00 is legal and means "end of that month" — 270600 is the end of June 2027. Year interpretation uses a sliding window around the current year, so two digits are unambiguous in practice.

Character set

Variable-length AI values use GS1's CSET 82 — digits, upper and lower case letters, and a limited set of punctuation. The space character is not included. A lot code of LOT 2027 is invalid; LOT-2027 is fine. This catches people out constantly because the space looks harmless.

Batch and serial: only if you need them

Encoding lot or serial data means every batch produces a different code, which means variable-data printing. That is a real cost. Add them when traceability, recalls, or expiry management justify it — not because the standard allows it.