\begin{sequencediagram}
    \newthread{actor}{Actor}{}
    \newinst[2]{concordia}{:Concordia}{}
    \newinst[2]{eth}{:Ethereum}{}
    \newinst[1]{orbit}{:OrbitDB}{}

    \begin{call}{actor}{Fetch topic}{concordia}{Topic}

        \begin{call}{concordia}{Get topic}{eth}{Topic}
        \end{call}

        \begin{call}{concordia}{Get topic post IDs}{eth}{Post IDs}
        \end{call}

        \begin{call}{concordia}{Get posts loop}{concordia}{Posts}

            \begin{call}{concordia}{Get post}{eth}{Post}
            \end{call}

        \end{call}

        \begin{call}{concordia}{Retrieve topic information}{orbit}{}
        \end{call}

        \begin{call}{concordia}{Retrieve posts information loop}{concordia}{Posts information}

            \begin{call}{concordia}{Retrieve post information}{orbit}{}
            \end{call}

        \end{call}
    \end{call}
\end{sequencediagram}