  One of the main problems of subspace coding asks for the maximum possible
cardinality of a subspace code with minimum distance at least $d$ over
$\mathbb{F}_q^n$, where the dimensions of the codewords, which are vector
spaces, are contained in $K\subseteq\{0,1,\dots,n\}$. In the special case of
$K=\{k\}$ one speaks of constant dimension codes. Since this (still) emerging
field is very prosperous on the one hand side and there are a lot of
connections to classical objects from Galois geometry it is a bit difficult to
keep or to obtain an overview about the current state of knowledge. To this end
we have implemented an on-line database of the (at least to us) known results
at \url{subspacecodes.uni-bayreuth.de}. The aim of this recurrently updated
technical report is to provide a user guide how this technical tool can be used
in research projects and to describe the so far implemented theoretic and
algorithmic knowledge.
