As high as possible, but at a minimum, contact someone whose compensation is at least partly based on online sales, because that's the factor you'll be most likely to influence. Titles will vary by company, but depending on the company, it could be the VP of Marketing, VP of Online Marketing, etc.

To eliminate guesswork, several of my portfolio companies have had great results by contacting the CEO's office (you'll get their assistant usually), with something like: "I have a visualization technology that can help your company increase online sales, who would be the best person to contact." Now you're 1) getting to the right person, and 2) coming from the CEO's office, so they can't blow you off.

If you haven't already, also consider how you can build up an intellectual property "fence" around your technology by filing for copyrights, trademarks and patents, as appropriate. This will help you minimize competitors down the road if you're successful, and also increase the enterprise value of your business in the event you ever want to sell it.

Book a call to get more detailed strategies on how to sell larger companies as a small startup and ways to protect your idea from vultures (both customers and competitors).