Format of Keys and ID's for Arduino LMIC library [HowTo]

In the TTN Console keys and id’s can be copied in different formats. If the format is not entered correctly in the application code then things are not going to work.

When using an Arduino LMIC library use the following formats for keys and ID’s:

Key/ID Description Format Custom C++ type Used for activation type
DevEUI end-device identifier lsb / little-endian u1_t[8] OTAA
AppEUI application identifier lsb / little-endian u1_t[8] OTAA
AppKey application key msb / big-endian u1_t[16] OTAA
DevAddr end-device address u4_t ABP
NwkSKey network session key msb / big-endian u1_t[16] ABP
AppSKey application session key msb / big-endian u1_t[16] ABP


lsb: least significant byte first
msb: most significant byte first