A bipartisan bill aimed at curbing the monopoly of tech giants on app stores was introduced by lawmakers Wednesday. The proposed legislation seeks to bring more competition to the app store market, dominated mostly by companies such as Apple and Google.

Introduced by Republican Senator Marsha Blackburn of Tennessee, Democratic Senator Richard Blumenthal of Connecticut and Democratic Senator Klobuchar of Minnesota, the bipartisan bill would significantly change how app stores operate by the establishment of new rules.

The proposed Open App Markets Act would bar companies that own app stores with more than 50 million users in the U.S. to limit developers from using only their own in-app payment systems. It would also prohibit the companies from banning or punishing developers that sell their digital products through other platforms.

Several developers have complained that they cannot make "legitimate business offers" to their customers outside of traditional app stores, which typically charge very high app store fees for in-app purchases. This has led to several lawsuits, including the ongoing legal battle between video games developer Epic Games and Apple.

Epic Games Vice President and Global Head of Public Policy Corie Wright called the proposed bill an "important milestone" in ensuring fairer digital platforms for developers.

Under the proposed bill, third-party app stores will better compete with those operated by tech giants such as Apple. Google currently allows third-party apps on its Android platform, but Apple only allows apps downloaded from its own Apple App Store.

Apple previously argued that allowing third-party app store downloads would pose a security risk. The company said its consumer's devices could become vulnerable if they are allowed to download and install apps from other sources.

Blumenthal said during an interview Wednesday that Apple and Google's arguments of why they need to place tight controls over their user's digital purchases are only a "pretext" to ensure their monopoly.

"It is not only disingenuous it's ironic because they're the ones who are actually invading privacy and stealing data from the developers, and all the while they're saying, 'Oh, well, we're the privacy protectors,'" Blumenthal said.

If the bill is passed, smartphone users could soon be able to "sideload" apps into their devices through third-party app stores. Users could also purchase digital products outside of their device's dedicated app stores, potentially at lower prices as developers no longer have to pay Apple and Google's steep app store fees.