If you live in Los Angeles, you are probably already intimately familiar with Watch Duty, the free app that shows active fires, mandatory evacuation zones, air quality indexes, wind direction, and a wealth of other information that everyone, from firefighters to regular people, have come to rely on during this week’s historic and devastating wildfires.

Watch Duty is unique in the tech world in that it doesn’t care about user engagement, time spent, or ad sales. The 501(c)(3) nonprofit behind it only cares about the accuracy of the information it provides and the speed with which the service can deliver that information. The app itself has taken off, rocketing to the top of Apple’s and Google’s app stores. Over 1 million people have downloaded it over the last few days alone. 

The elegance of the app lies in its simplicity. It doesn’t scrape user data, show ads, require any kind of login, or track your information. Its simple tech stack and UI — most of which is maintained by volunteer engineers and reporters — has likely helped save countless lives. While Watch Duty is free to use, the app accepts tax-deductible donations and offers two tiers of membership that unlock additional features, like a firefighting flight tracker and the ability to set alerts for more than four counties.

With plans to expand the service across the United States, as well as overseas and into other emergency services, Watch Duty may eventually replace some of the slower and less reliable local government alert systems for millions of people.

The idea for Watch Duty came to cofounder John Mills while he was trying to protect his off-grid Sonoma County home from the Walbridge fire in 2020. He realized there wasn’t a single source for all the information people needed to protect themselves from the blaze, which ultimately killed 33 people and destroyed 156 homes. John and his friend David Merritt, who is Watch Duty’s cofounder and CTO, decided to build an app to help.

“This came out of an idea that John had, and he talked to me about it four years ago,” Merritt tells The Verge. “We built the app in 60 days, and it was run completely by volunteers, no full-time staff. It was a side project for a lot of engineers, so the aim was to keep it as simple as possible.”

Fire reporting is piecemeal at best in fire-prone areas and frequently scattered across platforms like Facebook and X, where fire departments and counties have verified pages sharing relevant updates. But increasingly, social media platforms are putting automated access for alert services behind paywalls. Governments also use a wide variety of alert systems, causing delays that can cost lives, especially in fast-moving fires like the Palisades and Eaton fires that have forced evacuations for more than 180,000 people. And sometimes, these government-run alerts are sent out mistakenly, causing mass confusion.

Watch Duty simplifies all that for millions of people.

“We view what we are doing as a public service,” says Merritt. “It is a utility that everyone should have, which is timely, relevant information for their safety during emergencies. Right now, it’s very scattered. Even the agencies themselves, which have the best intentions, their hands are tied by bureaucracy or contracts. We partner with government sources with a focus on firefighting.”

One of the biggest issues around fires, in particular, is that they can move quickly and consume large swaths of land and structures in minutes. For example, the winds that drove the Palisades fire to spread to more than 10,000 acres reached 90 miles per hour on Tuesday. When minutes matter, the piecemeal alert system that Watch Duty replaces can cause delays that cost lives. 

“Some of the delivery systems for push notifications and text messages that government agencies use had a 15-minute delay, which is not good for fire,” says Merritt. “We shoot to have push notifications out in under a minute. Right now, 1.5 million people in LA are getting push notifications through the app. That’s a lot of messages to send out in 60 seconds. In general, people are getting it pretty much all at the same time.”

For Watch Duty, this kind of mass communication requires reliable technology as well as a group of dedicated staff and skilled volunteers. Merritt says that Watch Duty relies on a number of corporate partners with whom it has relationships and contracts to provide its service. 

The app is built on a mix of technology, including Google’s cloud platform, Amazon Web Services, Firebase, Fastly, and Heroku. Merritt says the app uses some AI, but only for internal routing of alerts and emails. Reporters at Watch Duty — those who listen to scanners and update the app with push notifications about everything from air drops to evacuation updates — are mostly volunteers who coordinate coverage via Slack.

“All information is vetted for quality over quantity,” he says. “We have a code of conduct for reporters. For example, we never report on injuries or give specific addresses. It’s all tailored with a specific set of criteria. We don’t editorialize. We report on what we have heard on the scanners.” 

According to Merritt, the app has 100 percent uptime. Even though it started with volunteer engineers, the nonprofit has slowly added more full-time people. “We still have volunteers helping us, but it’s becoming more on the internal paid staff as we grow, as things get more complex, and as we have more rigorous processes,” he says.

He says there are no plans to ever charge for the app or scrape user data. The approach is kind of the Field of Dreams method to building a free app that saves people’s lives: if you build it well, the funding will come. 

“It’s the antithesis of what a lot of tech does,” Merritt says. “We don’t want you to spend time in the app. You get information and get out. We have the option of adding more photos, but we limit those to the ones that provide different views of a fire we have been tracking. We don’t want people doom scrolling.” 

Watch Duty relies heavily on publicly available information from places like the National Weather Service and the Environmental Protection Agency. Should the incoming Trump administration decide to execute on threats to dismantle and disband the EPA (which monitors air quality) and the National Oceanic and Atmospheric Administration, the parent agency to the National Weather Service, such moves would impact Watch Duty’s ability to operate. 

Even still, Merritt is optimistic. “We will be pretty well insulated from any change to policy,” he says. “We are either buying that information ourselves already or we are happy to buy it, and we will take that cost on. The fact that we’re soon going to be covering the entire US will defray the cost of anything that shifts from a policy perspective. Our operation costs are mostly salaries. We are trying to hire really good engineers and have a really solid platform. If we need to raise a grant to buy data from the National Weather Service, then we will.”

Regardless of what the next administration does, it’s clear that Watch Duty has become a critical and necessary app for those in Southern California right now. The app currently covers 22 states and plans to roll out nationwide soon. 

“We got 1.4 million app downloads in the last few days,” according to Merritt. “I think we have only received 60 support tickets, so that shows that something is working there. We are really just focused on the delivery of this information.”