What chat software is NomadList using under the hood?

I'm not talking about their Slack but about this part:

I think Pieter wrote it himself, so it's a custom PHP+SQLite backend?

Gotcha, makes sense, and thank you!

He is quite good at visual design, I don't think people realise what a keen eye he got in that regard.

He is using PHP for coding, but the backend of the chat is also Slack. So if you send a message through the website chat, you can see the messages in Slack as well.

@SimJoSt Interesting. Does the bot sync them on Slack or does it ask the user to log in via Slack with permission to post messages on their behalf?

They are posted on my behalf. They look like normal messages.
Don't know how it works, if I am not creating a Slack account. Maybe he creates a dummy one for me behind the scenes.