At Quizlet, one of our highest throughput services, backed by MySQL, has been the source of multiple performance problems. In addition to the high throughput, the data managed by this service has a growth rate of ~2 billion records/month (and increasing!). At peak traffic, the service takes upwards of 10K writes/second. With scalability problems breathing down our neck, we decided to migrate our data and workload on to Cloud Spanner. There were challenges at every step of the way, from designing the schema, to migrating data, and getting a microservice serving from Cloud Spanner, without taking an outage. Did we succeed? What lessons did we learn along the way? Come find out.