Swappa offers a free ESN/IMEI check service: Check your ESN / IMEI
Swappa’s free IMEI check service reports whether a device is allowed (clean and ready for activation according to the GSMA global registry) or blocked (reported as lost or stolen).
If you don’t know the history of a device or are unsure about its activation status or any outstanding financial obligations, please contact the original wireless carrier before creating a listing.
Read more: How to find your phone’s IMEI