Massive list of free certificates and badges for developers in data science, software development, and more.

What if I told you that one man’s frustration with an elevator breakdown led to the creation of the fastest-growing and most-beloved programming languages today? Seventeen years ago, Graydon Hoare’s ordinary evening turned pivotal when an out-of-order elevator at his apartment building forced him to trek up 21 stories. A Mozilla software engineer, Hoare’s frustration wasn’t just with the climb, but with the fact that the tools of his trade couldn’t even make an elevator that works without cras

TL;DR Duolingo reported Q4 2025 revenue of $282.9 million (+35% YoY), closing its first billion-dollar year, breaking estimates again. The stock dropped 22.5% anyway. Again. The company plans to slow down monetization to grow to 100 million DAUs until 2028, by focusing on teaching quality, giving more to free users, and growing non-language courses. Duolingo’s Q4 2025 results confirmed something we highlighted in its 2025 review: growth is slowing. The company crossed a billion dollars in r

Find the Perfect Course and Become a Data Pro with Our Comprehensive Guide to the Best Online Data Science Courses.