Facebook’s Apps Went Down. The World Saw How Much It Runs on Them.

For more than five hours on Monday, the world got a taste of life without Facebook and its apps.

In Mexico, politicians were cut off from their constituents. In Turkey and Kenya, shopkeepers couldn’t sell their wares. And in Colombia, a nonprofit organization that uses WhatsApp to connect victims of gender-based violence to lifesaving services found its work impaired.

“Because we have a field team, we were able to mitigate some of the more serious risks today’s outage presented,” said Alex Berryhill, the director of digital operations for the group, Cosas de Mujeres. “But that might not have been the case for hundreds of other hotlines around the world. Today was a big reminder: Technologies are tools, not solutions.”

The Facebook outage on Monday was a planetary-scale demonstration of how essential the company’s services have become to daily life. Facebook, Instagram, WhatsApp and Messenger have long been more than just a way to chat and share photos. They are critical platforms for doing business, arranging medical care, conducting virtual classes, carrying out political campaigns, responding to emergencies and much, much more.

In parts of the developing world, the cost of the Facebook outage was particularly acute. In India, Latin America and Africa, its services are essentially the internet for many people — almost a public utility, usually cheaper than a phone call and depended upon for much of the communication and commerce of daily life.

The unease about a single corporation mediating so much human activity motivates much of the scrutiny surrounding Facebook.

In the United States, the Federal Trade Commission has filed an antitrust lawsuit against the company, accusing it of being a monopolist that acquired Instagram and WhatsApp to secure its dominance. European Union policymakers are drafting sweeping regulations that would crimp the company’s power.

In recent weeks, Facebook has been under fire after a whistle-blower, Frances Haugen, shared internal documents indicating, among other things, that the company knew Instagram was worsening teenagers’ body-image issues even while company executives publicly tried to minimize the app’s downsides.

The revelations have spurred more criticism from regulators and the public. On Tuesday, Congress was hearing testimony from Ms. Haugen about Facebook’s impact on young users.

Much of the recent criticism of Facebook has focused on the decisions the company’s leaders make — or fail to make — about governing, running and making money from its platforms. But as Monday’s outage demonstrated, another consequence of Facebook’s size is that many more people are affected when there are technical lapses like the ones the company says were responsible for the disruption.

In Brussels, the hub of the European Union — where many government workers have turned to the rival messaging service Signal to communicate amid concerns about Facebook’s reach — the outage led to a fresh round of calls for more oversight of the biggest tech platforms.

“In the global digital space, everyone could experience a shutdown,” Thierry Breton, the European commissioner drafting new tech regulations, said on Twitter. “Europeans deserve a better digital resilience via regulation, fair competition, stronger connectivity and cybersecurity.”

In India, Brazil and other countries, WhatsApp has become so important to the functioning of society that regulators should treat it as a “utility,” said Parminder Jeet Singh, executive director at IT for Change, a technology-focused nonprofit in Bengaluru, India.

People in India and other Asian countries where Facebook’s apps are popular largely slept through the outage, which occurred overnight for them. But Mr. Singh said the disruption still showed why regulators needed to supervise the internet giants more closely.

Worldwide, 2.76 billion people on average used at least one Facebook product each day this June, according to the company’s statistics. WhatsApp is used to send more than 100 billion messages a day and has been downloaded nearly six billion times since 2014, when Facebook bought it, according to estimates from the data firm Sensor Tower.

India accounted for about a quarter of those installations, while another quarter were in Latin America, according to Sensor Tower. Just 4 percent, or 238 million downloads, were in the United States.

In Latin America, Facebook’s apps can be lifelines in rural places where cellphone service has yet to arrive but the internet is available, and in poor communities where people cannot afford mobile data but can find a free internet connection.

Cosas de Mujeres, the nonprofit in Colombia, has hundreds of interactions every month with Colombian women and Venezuelan migrant women who face domestic and emotional violence or are at risk of trafficking or sexual exploitation, said Ms. Berryhill, the organization’s director of digital operations.

“Usually we have phone operators receiving messages from women all day via WhatsApp, but that was not possible, and women could not contact us,” she said.

María Elena Divas, a 51-year-old Venezuelan migrant in Bogotá, Colombia, uses WhatsApp to take orders for snacks like empanadas.

“I didn’t sell anything today,” Ms. Divas said.

Across Africa, Facebook’s apps are so popular that for many, they are the internet. WhatsApp, the continent’s most popular messaging app, is a one-stop shop to communicate with family, friends, colleagues, fellow worshipers and neighbors.

In Kenya’s capital, Nairobi, anything from shoes and jewelry to plants and household appliances can be ordered for delivery from Facebook, Instagram and WhatsApp. In Johannesburg, vendors were cut off from Facebook Marketplace, which is used to sell everything from used cars to wigs and even corrugated iron shacks, known colloquially as zozos.

The use of WhatsApp has grown so much that at one point it accounted for nearly half of all internet traffic in Zimbabwe. During the outage on Monday, the chief government spokesman in Tanzania used Twitter to urge the public to “remain calm.”

“Our business came to a standstill,” said Lydia Mutune, owner of a pots and plants store in Nairobi that sells exclusively on Facebook and Instagram. “It was a wake-up call. It just showed me how my business and our lives are totally dependent on social media platforms.”

In some places, people said that although the disappearance of Facebook’s apps hindered their work, it also removed a noisy distraction, making them feel better and more productive.

James Chambers was panicked at first for Chez Angela, the Canadian bakery he and his wife own in Brandon, Manitoba. They post four to five times daily on Facebook and Instagram to draw customers into the shop. But on Monday, he said, “as the day went on, we actually found more people coming in and saying that it was good to be disconnected.”

“We closed the day 30 percent above our normal Monday sale,” he added.

Drogasmil, a pharmacy chain in Brazil, takes many prescription orders via WhatsApp, said Rafael Silva, a Drogasmil pharmacist in Rio de Janeiro.

On Monday, there were none, but because he and his colleagues couldn’t chat on WhatsApp, the day felt “more serene,” he said.

Jan Böhmermann, a German comedian, tweeted that he wished Facebook, Instagram and WhatsApp would remain offline forever. His post received nearly 30,000 likes.

Surveys show that WhatsApp is installed on nearly every smartphone in Brazil and that most Brazilians with a phone check the app at least once an hour.

Restaurants take orders, supermarkets coordinate deliveries, and doctors, hairdressers and cleaners book appointments. During the pandemic, the app became a crucial tool for teachers to tutor students in remote areas of the country. It also has been central to the spread of disinformation.

In Russia, the authorities said the outage was evidence supporting the country’s crackdown on Western internet companies.

The disruptions “answer the question about whether we need our own social media and internet platforms,” said Maria Zakharova, a spokeswoman for the Foreign Ministry.

Still, in many places, people were struck by how the outage revealed their dependence on Facebook’s tools — and their vulnerability when the service is unavailable.

Selen Bayrak, owner of a small shop in Istanbul that sells spicy marmalades and sauces, said 80 percent of her sales were normally made through Instagram. She estimated that she managed to sell only a quarter of what she could have sold yesterday had Instagram not been down.

In Mexico, many small-town newspapers cannot afford print editions, so they publish on Facebook instead. That has left local governments without a physical outlet to issue important announcements, so they, too, have taken to Facebook, said Adrián Pascoe, a political consultant.

A municipality Mr. Pascoe is consulting for was unable to introduce its new services on Monday because the site was down. The announcement will take place on Wednesday instead, he said.

León David Pérez’s two companies, including Polimatía, which provides e-learning courses, rely on Facebook and Instagram to market their products. The customer service department is run on WhatsApp.

“The way businesses work, it’s been a crazy change in the last 20 years,” Mr. David said. “Then, we had no community online. Now we are hyper-connected, but we rely on a few tech companies for everything. When WhatsApp or Facebook are down, we all go down.”

Reporting was contributed by Maria Abi-Habib, Ian Austen, Lynsey Chutel, Abdi Latif Dahir, Steven Grattan, Valerie Hopkins, Jack Nicas, Christopher F. Schuetze and Julie Turkewitz.