Business Solution Provider (BSP) & Tech Provider
Updated
Quick answer: A Business Solution Provider (BSP) is a Meta partner that connects businesses to the WhatsApp Business API and can bill them for Meta's message charges. A Tech Provider is a Meta partner that onboards businesses through Embedded Signup while each business pays Meta directly. Advertz works as a Tech Provider, so your message charges go straight to Meta at Meta's rates with no markup.
The Meta partners that connect businesses to the WhatsApp Business API.
Both types provide the software — inbox, campaigns, chatbots. The difference that matters for cost is who bills you for WhatsApp messages and at what rate.