C Startups

Adam Wadden, a software engineer who also taught and made music, turned his frustration with poor PHP refactoring and testing resources into a self-published book and course, Refactoring the Collections. He built an email list and Twitter audience before a May launch with three pricing tiers, which made $25k on the first day and $65k in three days, and he then quit his job to build his next course. The source says he has done "two and a half million dollars in sales of his books and courses" since 2016.

Nylas, co-founded by Christine Spang, started as an effort to build a power-user email client but pivoted to a developer API that abstracts email, calendar, and contacts integration. The company launched its API as open source on GitHub, then moved to a per-connected-mailbox SaaS model, and now reports about 200 paying customers and revenue in the millions per year.