Google activated its “Person Finder,” and Facebook activated its “Safety Check” tools on the evening of Friday, November 13, to let anxious users check the status of friends and family caught up in the Paris terrorist attacks.

Mountain View-based Google.org (the company’s charitable division) engineers began working on its Person Finder feature after the January 2010 earthquake in Haiti. The apps were first deployed during the two-day crisis of the 2013 Boston Marathon bombing.

Menlo Park Facebook’s “Safety Check” launched in October 2014. The toll got its first workout in April following a 7.8-magnitude earthquake that struck Nepal. With the death toll at more than 1,000, the local communities discovered the apps, signed up, and were able to find many family members and friends. With phone service quickly overwhelmed, rescue workers who were frantically trying to free people trapped in rubble were able to direct resources to the hardest-hit areas through the apps.

Person Finder and Safety Check have the added feature of global availability on Android and iOS-enabled phones, desktops, and other devices.

Both apps send blast notifications to all potential users in an area that may be in a crisis, asking, “Are you safe?” Users can post, “I’m safe” or “I’m not in the area” and can also indicate that other people they are with are safe.

Twenty-four hours after the attacks, the confusion and panic in Paris are still intense. Recent reports estimate seven closely coordinated terrorist attacks that left at least 127 dead, 99 in critical condition, and 300 more injured.

The U.S. Embassy put out an official “Security Message” on November 13, 2015, during the attacks warning that “further incidents are possible.” U.S. citizens were advised to:

Maintain a high level of vigilance, be aware of local events, and take the appropriate steps to bolster their personal security, including limiting their movements to essential activity. U.S. citizens are encouraged to monitor media and local information sources and factor updated information into personal travel plans and activities.

Family and friends of Americans inundated the switchboard of the U.S. Embassy in Paris, desperately seeking to make contact with their loved ones. Despite over 1,000 State Department employees in Paris, the Embassy referred the callers to the ratp.fr website.

Worried Americans clicking the link were infuriated that when the site opened up, it was written in French. When translated, the site stated, “RATP joins national mourning following the appalling attacks in Paris and Saint-Denis Friday, November 13.”

The RAPT site told users, “For more information, click on the RER.” That site is also written in French, and when translated, it turns out to be the French public transportation link. The only information relevant to Americans on the site is notice that “Disney Land Paris Parks are closed.”

But within seconds of news reports of the frightening developments in Paris, Person Finder and Safety Check launched. The tools started updating the statuses on thousands of Americans in the “City of Lights” based on the city in their current profile or location of their Internet.