I'm new to the development network of salesforce, having come from hubspot platform.  To get started the quickest way, some Salesforce reps I spoke with suggested I get certified first in Lightning Certification.  However, on webassessor, I'm not seeing that certification or I'm missing the title.  Does anyone know which cert exam I should do to get started developing as a certified dev in that niche?

I;m also asking opinions on the type(s) of certications for salesforce to get the most traction with client needs.  Ie.  what certifications have the most demand so I can begin dev for Saleforce clients asap?