Web-based, Mac app, or open Git project?

I'd love to hear your suggestions for the best free programmer-friendly time tracking software available - to be used by myself, as the developer, on a solo full-stack web app build.

Something I can implement quickly and easily. No bells and whistles required for this project management software, however, it does need to be able to display task progress on the web (I don't mind hosting) to the Client in relatively-real-time.