Please always provide compilable code. It greatly reduces uncertainties, increases the prospect of questions being answered (a) at all and (b) in ways which actually help their askers, is much more efficient, more helpful to new users and generally makes life much easier.
Guessing how to complete your code, I'm also not clear if you really mean labels or if you want to change the nodes' content. I'm assuming the latter as labels make little sense here, as far as I can tell. That is, I take the target to be something like this:

If so:
\begin{forest}
for tree={
grow'=0,
align=center,
base=bottom
},
before typesetting nodes={
for tree breadth-first={
if level=0{temptoksa=1}{
temptoksa/.option=n,
for nodewalk={
while nodewalk valid={u}{u,+temptoksa=.,if level=0{+temptoksa=1}{+temptoksa/.option=n}}
}{},
},
content/.process={ROw2{temptoksa}{content}{#1 #2}}
}
}
[Deadbeef
[Something
[Generic\\node]
[Other\\ generic node]
[That one\\there]
]
[Else
[Client\\Side
[Become\\data]
[Bathe in\\data]
]
[Server\\Side
[One with\\data]
[Meta\\data
[Update\\main service]
[Update\\database]
]
]
]
[Kindof
[You are\\very kind]
[How much\\for the lot?]
[Really not\\serious]
]
]
\end{forest}
Incidentally, the tree does not look very clear to me, because the edges often end randomly in relation to their children. I would probably go for something more like this:
for tree={
grow'=0,
align=center,
font=\sffamily,
},
forked edges,
align middle children,
in the tree's preamble, where align middle children
is from a custom library and defined as follows:
\forestset{
align middle child/.style={
before typesetting nodes={
if={
> Ow+P {n children}{isodd(##1)}
}{
calign child/.process={
Ow+n {n children}{(##1+1)/2}
},
calign=child edge,
}{},
},
},
align middle children/.style={
for tree={align middle child},
},
}

But that's a matter of taste, of course.
Complete code:
\documentclass[border=10pt]{standalone}
\usepackage[edges]{forest}
\forestset{
align middle child/.style={
before typesetting nodes={
if={
> Ow+P {n children}{isodd(##1)}
}{
calign child/.process={
Ow+n {n children}{(##1+1)/2}
},
calign=child edge,
}{},
},
},
align middle children/.style={
for tree={align middle child},
},
}
\begin{document}
\begin{forest}
for tree={
grow'=0,
align=center,
base=bottom
},
before typesetting nodes={
for tree breadth-first={
if level=0{temptoksa=1}{
temptoksa/.option=n,
for nodewalk={
while nodewalk valid={u}{u,+temptoksa=.,if level=0{+temptoksa=1}{+temptoksa/.option=n}}
}{},
},
content/.process={ROw2{temptoksa}{content}{#1 #2}}
}
}
[Deadbeef
[Something
[Generic\\node]
[Other\\ generic node]
[That one\\there]
]
[Else
[Client\\Side
[Become\\data]
[Bathe in\\data]
]
[Server\\Side
[One with\\data]
[Meta\\data
[Update\\main service]
[Update\\database]
]
]
]
[Kindof
[You are\\very kind]
[How much\\for the lot?]
[Really not\\serious]
]
]
\end{forest}
\begin{forest}
for tree={
grow'=0,
align=center,
font=\sffamily,
},
forked edges,
align middle children,
before typesetting nodes={
for tree breadth-first={
if level=0{temptoksa=1}{
temptoksa/.option=n,
for nodewalk={
while nodewalk valid={u}{u,+temptoksa=.,if level=0{+temptoksa=1}{+temptoksa/.option=n}}
}{},
},
content/.process={ROw2{temptoksa}{content}{#1 #2}}
}
}
[Deadbeef
[Something
[Generic\\node]
[Other\\ generic node]
[That one\\there]
]
[Else
[Client\\Side
[Become\\data]
[Bathe in\\data]
]
[Server\\Side
[One with\\data]
[Meta\\data
[Update\\main service]
[Update\\database]
]
]
]
[Kindof
[You are\\very kind]
[How much\\for the lot?]
[Really not\\serious]
]
]
\end{forest}
\end{document}