This is a web application for ApisCP.
cd /usr/local/apnscp
git clone https://github.com/LithiumHosting/apiscp-webapp-blesta config/custom/webapps/blesta
./composer dump-autoload -o
Edit config/custom/boot.php, create if not exists:
<?php
\a23r::registerModule('liblesta', \lithiumhosting\blesta\Blesta_Module::class);
\Module\Support\Webapps::registerApplication('blesta', \apisnetworks\blesta\Handler::class);
Then restart ApisCP.
systemctl restart apiscp
Voila!
All third-party documentation is available via docs.apiscp.com.