Impulso.
Counting starts with the gun at 5:50am Saturday and everyone begins on zero. Most steps from there to Sunday night wins, with a $1,000 pool shared across the top three.
Free to download. No subscription, no entry fee.
You don't need a bib. The Stromlo Challenge is open to everyone, so you can take part from wherever you are.
Fair warning though. A half marathon is around 27,000 steps before anyone has even left the event, so the runners are going to be very hard to beat.
Stromlo is a one off, but Impulso runs comps all year. One day comps every Monday, Wednesday and Friday. Week long step comps. And Team vs Team, where you grab a mate and the winning team splits the prize. All free to join.