A Flutter plugin for retrieving the uid of a device
To retrieve the id just import and call String device_id = await DeviceId.getID;.
To retrieve the imei call String imei = await DeviceId.getIMEI;.
To retrieve the meid call String meid = await DeviceId.getMEID;.
For imei and meid platform version >=26 is required, otherwise it will produces a PlatformExcpetion
Now you are good to go!
Note: device ids are not safe as you think, rooted/jailbreaked devices are able to change the ids.