The pandemic has fueled the growth of online services startups, particularly those related to health care and emergency services.

AlertMedia, which helps companies send warnings to employees about dangerous situations like tornadoes and active shooters, saw its number of customers increase nearly 50% last year. Now it’s selling a controlling stake to investment firm Vista Equity Partners to fund further growth.

CEO and founder Brian Cruver says he plans to expand the company internationally and into new segments beyond the industries it has already targeted, like transportation and retail. “We’re taking what were our plans for the next five or 10 years and doing them in two or three years,” he says.

Cruver and Vista declined to discuss terms of the deal, though a source familiar with the matter says the investment totals $400 million. The Austin-based company has previously raised about $60 million in venture capital from investors including Silverton Partners and JMI Equity. Austin’s startup scene was hit hard during the pandemic, but it could make a strong comeback once the disease subsides, as Texas is gaining businesses from California, including Oracle’s and Hewlett Packard’s headquarters.

AlertMedia offers an emergency communications dashboard that helps customers send rapid messages to any or all employees during emergencies. If a wildfire threatens a factory in California, for example, a company could send warnings just to employees of that plant over text messaging, emails, automated phone calls, and other communications methods.

Customers pay a monthly fee based on the number of employees and where those employees are located. A typical customer with 1,000 worldwide employees would pay $15,000 to $25,000 a year. AlertMedia has 2,500 customers with employees in 130 countries, including Coca-Cola, DHL, and Walmart. Smaller customers range from golf courses to zoos to nursing homes.

AlertMedia is adding a new premium service that involves sending companies reports about potentially risky situations, known as threat intelligence.

Other small startups in the workplace-alert market include San Francisco–based Regroup, Konexus in Boise, and Klaxon Technologies in the U.K. Larger software developer Everbridge offers an alert service more like AlertMedia’s product.

Cruver says the idea for the company came to him in 2013 as he witnessed events like the Boston Marathon bombing and the Newtown School shooting. Government officials released information slowly to the public, while ordinary people stepped up by using social media to alert neighbors about local dangers.

“If you really wanted to know what was going on, you went to Facebook and Twitter,” Cruver says. “It felt like a shift to me in the way the crowd was sourcing the information.”

But Cruver’s idea was not to rely on Twitter or other public social media for issuing alerts. Instead, AlertMedia uses modern communications tools to share information privately among workers. “Social media is the Wild West,” he explains. “We’re using social media–like private channels.”

During one year early in his career, Cruver worked at energy-trading giant Enron before it went bankrupt. He ended up writing a book about what he witnessed, Anatomy of Greed, that was later made into a movie. The experience informs his approach as CEO, as he seeks to create a company culture that’s the “anti-Enron,” he says. “The mission should be a positive for society,” he says.

In a typical crisis, an AlertMedia customer can use the system to warn employees and track the responses back from the workers as they indicate whether they are safe or in danger.

During the pandemic, customers have been using the system to help with the return to working in person. Companies can use the survey tool to ask employees coming to the office on a particular day whether they’ve had any symptoms or close exposure. If an employee tests positive, the system can warn those who’ve had close contact to quarantine.

AlertMedia’s growth and usefulness during the pandemic caught the attention of Vista, a $73 billion investment firm that focuses on software, data, and technology companies. “With the COVID-19 pandemic, protecting the health and safety of employees while maintaining the ability to serve customers in a crisis has become an organizational imperative and competitive advantage,” Ryan Atlas, managing director at Vista, said in a statement.

(Correction: This story was updated on March 10 to correct that a typical customer would pay $15,000 to $25,000 per year.)