EcCodes is an evolution of GRIB-API. It is designed to provide the user with a simple set of functions to access data from several formats with a key/value approach.
For GRIB encoding and decoding, the GRIB-API functionality is provided fully in ecCodes with only minor interface and behaviour changes. Interfaces for C, Fortran 90 and Python are all maintained as in GRIB-API. However, the GRIB-API Fortran 77 interface is no longer available.
In addition, a new set of functions with the prefix "codes_" is provided to operate on all the supported message formats. These functions have the same interface and behaviour as the "grib_" functions.
You can find documentation on the module, with the command:
module help eccodes