Unidata supports netCDF APIs in C, C++, Fortran 77, Fortran 90, and Java.

The netCDF Java API is a complete implementation of netCDF in Java. It is distributed independently of the other APIs. If you are writing web server software, you should certainly be doing so in Java.

The main netCDF distribution contains the C library and the netCDF utilities, ncgen/ncdump/nccopy.

The C++, Fortran 77 and Fortran 90 APIs are distributed separately from the C library. The C library must be installed before any of these APIs may be built. They depend on the C API.

Due to the nature of C++ and Fortran 90, users of those languages can also use the C and Fortran 77 APIs (respectively) directly.

Full documentation exists for each API (see NetCDF Documentation).

In addition, many other language APIs exist, including Perl, Python, and Ruby. Most of these APIs were written and supported by netCDF users. Some of them are listed on the netCDF software page. Since these generally use the C API, they should work well with netCDF-4/HDF5 files, but the maintainers of the APIs must add support for netCDF-4 advanced features.

In addition to the main netCDF-3 C API, there is an additional (older) C API, the netCDF-2 API. This API produces exactly the same files as the netCDF-3 API - only the API is different. That is, users can create either classic CDF-1 format files, the default, 64-bit offset files (CDF-2), 64-bit data files (CDF-5), or netCDF-4/HDF5 files.

The version 2 API was the API before netCDF-3.0 came out. It is still fully supported, however. Programs written to the version 2 API will continue to work. The version 2 API is built with the netCDF library by default.

Users writing new programs should use the netCDF-3 API, which contains better type checking, better error handling, and better documentation.

The netCDF-2 API is provided for backward compatibility. Documentation for the netCDF-2 API can be found on the netCDF website, see https://www.unidata.ucar.edu/netcdf/old_docs/really_old/guide_toc.html.