A locked phone only works with one network's SIM. Check before you buy it, switch network or travel with an eSIM.
Dial *#06# on the phone, or look in Settings, About.
You are only charged once your report is ready. Apple Pay, Google Pay or a bank-verified card.
Open Settings, General, About and look at Carrier Lock. "No SIM restrictions" means it is unlocked. If you only have the IMEI, for example before buying, the full report shows the lock status and the locked network.
The reliable test is a SIM from a different network. If it connects, the phone is unlocked. Lock status by IMEI is available for iPhones; for Android the free check still confirms the phone is not blacklisted.
Yes. A travel eSIM is a plan from a different provider, so a network-locked phone will refuse it. Check the lock before you travel.
No. Unlocked means the phone accepts any network's SIM. Blacklisted means networks refuse to serve it at all. A phone should be both unlocked and clean.
Dial *#06# on the phone and the 15-digit IMEI appears on screen. It is also in Settings under About, and printed on the original box. On a dual-SIM phone use IMEI 1.
No. It shows what the device databases hold at the moment of the check. Records can change, for example if a phone is reported stolen later, so check the phone in person before you pay for it.
For $1.79 the full report adds the blacklist history and, on iPhones, the network lock, Find My iPhone and iCloud status and the warranty, with a plain list of what to sort out with the seller. You are charged only once the report is ready, and not at all if it cannot be completed.