Apple and Google have agreed to make their mobile app stores fairer and more transparent for developers, Britain’s Competition and Markets Authority (CMA) said on Tuesday, describing the commitments as an important first step under its tougher competition regime.

The CMA designated the two U.S. tech giants as having “strategic market status” in the smartphone sector in October, granting the regulator powers to impose targeted measures to boost competition.

Nearly all smartphones in Britain run either Apple’s iOS or Google’s Android operating systems, giving their app stores and browsers dominant positions on their respective platforms.

Under the commitments, Apple and Google have agreed to review apps in a fair, objective and transparent manner, the CMA said. Developers will also be able to request access to more of Apple’s iOS features to build competing products, including services related to digital wallets and live translation.

The regulator has previously warned that the companies’ dominance allows them to exert significant influence over digital content, services and technological development.

Apple said it faces “fierce competition in every market where we operate” and that the commitments would allow it to continue advancing privacy and security innovations while supporting developer opportunities.

Google said it believed its existing developer practices were already fair, objective and transparent, but welcomed the opportunity to address the CMA’s concerns collaboratively.