APN settings generator
Enter your APN and, if needed, username, password and authentication type, and get the exact configuration for three targets: AT commands (AT+CGDCONT / AT+CGAUTH per 3GPP TS 27.007), ModemManager with nmcli on Linux, and the fields to fill in on Android. Everything is generated in your browser.
Generated configuration
AT+CGDCONT=1,"IP","internet"
Why the APN matters (and why it's usually the only thing that breaks)
The APN (Access Point Name) is the name of the access point that tells the network which data gateway to connect your device to. Without the right APN the modem registers on the network — it even shows good signal — but never gets an IP address or carries data. In AT commands it's defined with AT+CGDCONT, giving the context identifier, the PDP type and the APN itself; if the operator requires a username and password you add AT+CGAUTH with the PAP or CHAP protocol. On Linux, ModemManager does the same with a single nmcli line, and on Android it's a few fields in the APN menu. Many IoT SIMs need no username or password and use "None" authentication; adding them when they aren't needed is as common a cause of connection failures as forgetting them when they are.