PomoBotto

Simple, but you shouldn't need more. It pings you when you when your timer is up. You can set your work and break duration through parameters. When timer is up, you get a choice to start either another work session or a break session.

The two commands are /pomo-start - with work and break duration in minutes /pomo-check - to check on your existing timer.

It's open source, run it yourself if you want: https://github.com/ellyxir/pomodoro_bot

There is no logging stored nor is there an upsell version.