Joe Previte teaches a course on TypeScript, offering a free email course with 3 modules that teaches how to ship TypeScript production code faster and safer than any other course out there, currently with over 1,500 subscribers and high ambitions to become a million-dollar course.

Vuetify is a popular open-source user interface library, built with the Vue.js framework, that generates revenue through digital content and services such as paid digital content in the Vuetify store, direct support through consulting, ad revenue from Carbon ads on the documentation pages, and donations/sponsorships via GitHub and Patreon, generating an average income of $6,500 per month.

Gikken is a small, profitable European company founded by Alex that makes browser extensions and apps used by 800,000 people every month, with their flagship product, Mate Translate, generating around $18,000 a month, but monetizing their user base better is their top priority for the next year.

Mockoon, an open-source desktop application that allows developers to easily and quickly mock any REST API, has reached 100k downloads and has 10k monthly active users without any monetization, using a combination of GitHub, Firebase hosting and Cloudflare, and focusing on growth through positive feedback and word of mouth.