We download the OCONUS and Foreign Location per diem rates on a monthly basis from the following site Per Diem Rate Files (dod.mil) . The CONUS Location rates effective October 1st of each year are downloaded from the following site Per Diem Rate Files (dod.mil).
You can also reference Per Diem Rates | GSA for more information.
For Meals breakdown we use the following: M&IE Breakdown | GSA
If you have any questions please reach out to support@data-basics.com