Libaec provides fast lossless compression of 1 up to 32 bit wide signed or unsigned integers (samples). The library achieves best results for low entropy data as often encountered in space imaging instrument data or numerical model output from weather or climate simulations. While floating point representations are not directly supported, they can also be efficiently coded by grouping exponents and mantissa. Libaec implements Golomb-Rice coding as defined in the Space Data System Standard documents 121.0-B-2 and 120.0-G-2. Libaec includes a free drop-in replacement for the SZIP library. Just replace SZIP's shared library libsz.so* with libaec.so* and libsz.so* from libaec. Code which is dynamically linked with SZIP such as HDF5 should continue to work with libaec. No re-compilation required. HDF5 files which contain SZIP encoded data can be decoded by HDF5 using libaec and vice versa.