UDID vs serial number vs IMEI
iPhones and iPads have several identifiers, and they are easy to confuse. UDID, serial number, and IMEI all identify something different and are used in different workflows.
UDID
The UDID is commonly used in Apple development, app testing, provisioning, and device management contexts. If a developer asks for your device identifier for a test build, they usually mean UDID.
Serial number
The serial number identifies hardware for support, warranty, repairs, and inventory. It is useful for Apple support and asset tracking, but it is not a replacement for a UDID in app provisioning workflows.
IMEI
IMEI identifies the cellular modem in devices that have cellular hardware. Carriers use it for network and device eligibility workflows. Wi-Fi-only iPads may not have an IMEI.
Need the identifier?
Get your UDID in Safari
Open this page on the iPhone or iPad you want to identify and use the profile flow to copy the result.
Common questions
Which identifier should I send to a developer?
If they asked for a UDID, send the UDID exactly. Do not send the serial number or IMEI unless they asked for those separately.
Can UDID Tools show more than the UDID?
Yes. When iOS provides the values, UDID Tools can show device model, OS version, serial number, IMEI, MEID, and related technical details.