Tomorrow, the biggest sporting event in the world — the World Cup — kicks off in Brazil. At Fast Company, Neal Ungerleider writes about how Twitter is working to ensure their service doesn’t buckle from the massive surge in traffic:

Raffi Krikorian is one of Twitter’s main engineers who keeps the service’s backend working. Krikorian, a vice president of platform engineering, helms a team (which encompasses approximately one third of Twitter’s software engineers) responsible for preventing outages and making sure the service is available.

“I’ve been here just shy of five years, and I still have PTSD from the last World Cup at Twitter,” Krikorian told me. “When you come to my floor at Twitter headquarters, we have signs all over the floor with a countdown to the World Cup. Reliability is at the top of our minds, and reliability first is the mantra. Somewhere in the world, there is a sporting event, an election, or an earthquake.”

But it also poses very specific engineering challenges for Twitter. Krikorian’s team plans for the World Cup using worst-case scenarios of extremely high site traffic. One hypothetical he brought up on the phone was a Brazil-Japan match; Twitter’s market penetration in Japan is massive and a Japanese television show holds the record for inspiring the most tweets-per-second.

Four years ago, the World Cup created a whopping 150,000 tweets per hour. Given how much the service has grown in popularity since then, expect that number to be even more massive this year.