Some U.S. users of the Facebook app will see an "add a link" option next to buttons to add photos or a location to a status post.
A user will type in a search term and then a drop down list of links will appear. The user will be able to preview what is on that website and then share the link on the social networking site.
Typically a user would have to search on Google or other search engines or go directly to a website and copy and paste the link into Facebook. The social networking giant is working on cutting out that process and keeping people inside the Facebook app for as long as possible.
"We're piloting a new way to add a link that's been shared on Facebook to your posts and comments," a Facebook spokesperson told TechCrunch on Sunday.
Facebook has indexed one trillion posts that have been shared on users' feeds. This will allow the in-app search engine to suggest the most shared links. This data will allow Facebook to steal a march on Google, experts warn.
This, coupled with advertising opportunities could worry Google, according to analysts, given the stiff competition for mobile ad dollars.
"If you look at Facebook's progress over the last few years, the real growth has been in its mobile advertising revenue," Jack Kent, senior mobile analyst at IHS, told CNBC by phone.
"That means that Facebook's mobile advertising growth will put pressure on Google. And anything which keeps people inside Facebook with an experience that means that you don't need Google would put pressure on Google."
Over 70 percent of Facebook's total advertising revenue comes from mobile and the company has been working hard to keep people in the app for longer.
Another attempt by Facebook to keep its users away from search engines is news. A report in the New York Times this year suggested Facebook was in talk with news publishers to host content on the social networking site rather than linking back to the publisher's website. The aim would be to share ad revenues.