[fecak]

I'm a professional resume writer and former tech recruiter, and I'd say "it depends".

Does the side project demonstrate a specific skill that you don't have in your day job that can/will be attractive to the hiring company? (if yes, include)

Does the side project have any popularity or adoption that would potentially make it impressive? (if yes, include)

Does the side project demonstrate your ability to solve problems within the hiring company's domain? (if yes, include)

Does the side project show some level of versatility that your professional body of work lacks? (if yes, include)