Superhuman is one of the most in-demand startups right now, with the invite-only app considered one of the most exclusive services in the tech industry. That’s impressive, for an email app. It’s even more impressive for an email app that merely accesses your existing Gmail account and costs $30 per month to use. The buzz — both from the company’s marketing and around Silicon Valley — is off the charts. Superhuman bills itself as “not another email client,” promising an inbox that’s been “rebuilt from the ground up” that will make you “feel like you have superpowers.” The website is peppered with accolades from startup CEOs praising how it has changed their relationship with email.