Why Maintaining core‑js Became My Biggest Mistake – Lessons for Full‑Time Open‑Source Developers

core‑js author Denis Pushkarev recently published a long article titled “So, what's next?” in which he intended to outline the next major version and roadmap of core‑js, but instead devoted much of the text to reflecting on his open‑source journey and the challenges he has faced.

core‑js is one of the most popular polyfill libraries for the JavaScript standard library, providing support for the latest ECMAScript specifications and proposals so that older browsers can use modern APIs.

Denis admits that maintaining core‑js may be the biggest mistake of his life. He left a high‑salary job to work full‑time on the project, received only $57 in donations in the last month, and added a job‑search notice to the core‑js CLI, which attracted unfriendly reactions.

After a motorcycle accident that resulted in one injury and one death, he was sentenced to 18 months in prison, a two‑year driving ban, and a fine of 1.38 million rubles, exhausting his savings. He also mentions being “specially treated” by certain TC39 committee members who set obstacles for him.

Now a father, Denis can no longer rely on donations to support his family. He is exploring sustainable solutions for core‑js, such as securing stable financial backing or changing the license to allow commercial use.

To help full‑time open‑source contributors address basic living needs, the article includes advice such as seeking sponsorship on platforms like Patreon or Open Collective, finding remote paid work, leveraging open‑source experience to increase employability, collaborating with other developers, targeting supportive employers, and attracting sponsors when a project gains traction.

Additional recommendations cover time management, maintaining health, reducing personal expenses, and regularly evaluating one’s commitment to ensure a balanced and sustainable open‑source career.

The piece also lists several international and Chinese independent developers who have successfully monetized open‑source projects through donations, paid support, advertising, product add‑ons, commercial licenses, event sponsorship, consulting, training, and related services.