> ## Documentation Index
> Fetch the complete documentation index at: https://docs.qlero.io/llms.txt
> Use this file to discover all available pages before exploring further.

# Add foreign identifiers or aliases for tracks or releases

## Overview

Both tracks and releases can carry a Foreign ID and a list of Aliases. They serve different purposes: a Foreign ID is for cross-referencing Qlero with another system, while Aliases let Qlero recognise a track or release when sales come in under a different code.

## Foreign ID

A Foreign ID is a single optional value used to store an identifier from another system, such as a DSP catalogue or an internal database. It is set on the track or release directly and is not used to match incoming sales — it exists purely as a reference for your own systems and integrations.

## Aliases

Aliases are a list of additional identifiers attached to a track or release. When sales arrive referencing one of the aliases, Qlero matches the sale to the correct track or release. Common uses include an alternate ISRC for the same recording, or an internal code used by a distribution partner.

## Rules and behaviour

**Unique within the record company** — The same alias cannot be attached to more than one track or release. If you try to add an alias that is already in use, you will get an error.

**Case-sensitive** — *ABC123* and *abc123* are treated as different aliases.

**Set on create or update** — Aliases can be added when the track or release is first created, or added later.

**Replace, not append** — Updating the list of aliases replaces the previous list. To keep existing aliases when adding a new one, include them in the updated list as well.