Eventbrite has now processed more than $8B in Gross Ticket Sales (since inception), and over $3B in 2016 alone. In 2017, they supported nearly 3 million events in 180 countries. So when it came time to give their apps' front-end an upgrade, it didn't happen overnight. We spoke with Marcos Iglesias and Ryan Wholey from the Evenbrite engineering team about how they're moving from Backbone + Marionette + D3 to React + a new charting library they built on top of D3 called Britecharts.