Create a basic WiFi captive portal

I need a simple captive portal solution for a WiFi hotspot. This will be coded from scratch in something like nodejs or golang. There are nodejs packages available for ipTables. The OS will be Linux/BSD based. The captive portal will be able to serve a captive portal web page that I have to wifi users upon connection. Data will be logged to remote API. There will be a basic web admin panel with simple controls for network, iptables firewall etc. Some basic statistics will be shown in the admin panel.