One of the best ways to build experience and grow your skillset is through a side hustle. There is nothing wrong with using that side hustle experience in your resume. On the contrary, it can be the information that puts you over the top for that dream job.
Valid Side Hustle Experience
There are good and bad uses of this experience. Flagrant misuse of a title (e.g., CEO of your one-person company) is not helpful. However, you will gain valid and useful experience and skills as part of these endeavors. Some of this experience is almost impossible to have outside of a long and deep resume, which makes it that much more valuable. Technical skills, design, and even client interactions are often examples of side hustle experience that is perfectly valid on a resume.
Think Like A Normal Job
There are all types of tasks and roles you take on as part of a development team. These could be downplayed as you being part of a team. On the other hand, you did gain experience from it. A side hustle is no different in this aspect. You did the work, whether it was for a fortune 100 company or as a favor to a family member. The process will understandably be different. Nevertheless, there are skills required to get it done, and those can flesh out a resume.
Add A Finishing Touch
One of the best ways to gain from side hustle experience is to try to do it using best practices. This is not always possible in the real world, but sometimes our side hustle can be framed in a way that allows us to take steps we often would have to skip. Instead of cutting corners because it is a personal project, step up the quality and process. Your resume will thank you.