You know what they say about building software: It’s not just a job—it’s a passion. Okay, nobody really says that. Nonetheless, it’s true: when developers and other tech pros leave their jobs, they keep coding through the night and on weekends. Based on data in the annual Octoverse report, which breaks down the activity of 31 million developers on the Github platform, contributions to public and open-source code repositories dip but don’t flatten out on Saturday or Sunday, even as activity on private repositories plunges. In other words, a significant percentage of tech pros contribute code to their companies (i.e., the private repositories) up to Friday evening—and keep merrily coding their own projects (the open-source and public repositories) through the weekend. Nor is that activity restricted to the United States; around the world, tech pros engage in similar patterns throughout their workweek. A similar pattern dominates the workday: work in private repositories rises during the morning and falls in the late afternoon, while contributions to public and open-source repositories dips slowly throughout the night. Only after midnight does activity on all types of repositories drop, as tech pros aim to get a few hours’ shut-eye before the workday gears up again. According to Stack Overflow’s (extensive and essential) Developer Survey, more than 80 percent of developers code as a hobby outside of work. Not only that, but those developers with extensive non-programming responsibilities, such as parenting or an affinity for the outdoors, were “slightly more likely to code as a hobby than other groups.” In 2017, another survey by Stack Overflow (unrelated to their Developer Survey) found that developers tend to engage with different programming languages in their hobbyist work than their day-jobs; on weekends, they used Haskell, Assembly, and OpenGL, in contrast to workweeks dominated by the likes of Sharepoint, Powershell, and other, more enterprise-centric platforms. “If we look for the tags that have increased the most in weekend activity, we see the game engine Unity3D, as well as a number of tags used for building mobile apps,” Stack Overflow noted at the time. “It looks like developers are designing more games and apps on the weekends now than in previous years.” It seems unlikely that those trends have wavered much over the past year; many developers enjoy toying with the newest languages and platforms to come onto the market, even ones that have no bearing on their salaried work. In any case, for many developers, coding isn’t just a job—it’s a… okay, okay, we’ll stop now.