Hi,
the service exists.
See this great pitch: https://www.youtube.com/watch?v=apqki21fWss
Good luck
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Even if this platform exists doesn't mean there isn't an opportunity. It's all about how you market it and get it in front of the right companies. I work at a 30 person startup and I can say 1. We (and many of our peers) aren't aware of these platforms today and 2. We could definitely use it throughout the year. The business model I'd recommend would be charging the vendors and making it free for companies to use. The hardest part will be convincing companies to use it over another option or just paying for something they can do themselves so you have to showcase value + no risk. You then build a base of customers and then vendors would be happy to pay to have access to these customers as it would be relatively cheap/easy ways for them to acquire new customers. If you come to a vendor and say "I have 100 companies on my platform and I charge you 15% of the revenue you drive from them", I'm not sure why they wouldn't do that as it would be pure incremental revenue/profit for them. And maybe to further stand out they could offer your companies discounts which then in turn adds more value to the brands. Seems like it would be a win-win-win for everyone