I joined the company right after it finishedTechStars. Initially I focused on customer development, but eventually I weaseled my way into CTO.
How it works
We created an API and code libraries that made it a snap to instrument your app for collecting metrics, then pushing them to StatsMix for analysis. For example, a mobile app developer may want to track how many times per day that users perform an action. StatsMix makes tracking simply a matter of adding one line of code to inline with the event you want to track. Once that's deployed, you can login to the StatsMix web app and view the metric on a chart. You can also combine multiple metrics together on a dashboard.
Also, StatsMix has plug-ins for popular services such as Google Analytics, allowing you to import that data and display it on your dashboards.
Challenges I ran into
Scaling was tricky. When I joined we had a monolithic database containing all metrics for all customers. The solution was to shard it into multiple databases, one for each client (and in some cases one for each metric). This dramatically improved response time. The tradeoff is it complicated schema migrations and backups.
Accomplishments that I'm proud of
Scaling it to handle millions of data points per day with fast response time.
What I learned
This was my first Ruby on Rails project, so I learned a ton about how that works. It was also my first time building (and documenting!) a REST API.