What are mobile browsers and browser engines?

Mobile device users access the internet through a mobile browser. Mobile browsers are comprised of two main elements, being a browser engine and the browser user interface (UI).

Browser engines are responsible for interpreting the source code of each web page. Browser engines are responsible for web compatibility (ensuring browsers can access and display content on a web page) and determine the range of possible user inputs, such as camera, microphone or video game controller. The three main browser engines are Google’s Blink, Apple’s WebKit and Mozilla’s Gecko.

The browser UI sits on top of the browser engine and is responsible for features such as bookmarks, browsing history, and remembering passwords. Users would be familiar with browser UI such as Chrome, Edge, Safari, Firefox, and Samsung Internet.

Bear in mind, because it will be important to understand the business case for browsers, that ‘browse’ is different to ‘search’: a browser has to be coupled with a search engine. This means that browsers are an important ‘mediator’ between search engines and end users, but search is the ‘font of the revenue’.

What does the browser market look like?

Many operators distribute their own browsers. Browsers can be a dedicated standalone app sitting on your phone, or apps (such as Snapchat) can have their own inbuilt browsers which allow users to access web content without opening another browser.

However, the CMA found that the supply of browsers is concentrated between Google’s Chrome and Apple’s Safari: in 2020, Safari’s share is 48% on mobile devices while Chrome’s share is 40% on mobile devices. The supply of browser engines is also concentrated between Google’s Blink, with just under 50% on mobile, and Apple’s WebKit, with just over 50%.

What is the browser business case?

Browsers are not directly monetized: browsers are pre-installed or can be downloaded for free and there is no charge to use a browser to access web content. The three major browser search engines are also open source and are not directly monetized.

The main source of revenue for browsers is the search engines to which they direct traffic.

Browser vendors can set their own search engines as the default, but following a European Commission decision, Google now provides for users to choose their search engine for Chrome (although the CMA says that nearly every user chooses Google Search).

Browser vendors without their own search engine sell off the default setting: in the UK, Google pays over GBP 1 billion annually for third party browsers, including Apple’s Safari, to direct traffic to Google Search.

Browsers also play a role in enabling businesses to monetize their content by serving users with advertising (or ‘ads’). These businesses, and the ad tech intermediaries operating on their behalf, in many cases collect and use data about users’ browsing behavior, in order to display targeted ads to them.

Browsers also can be developed and distributed by vendors to complement their other products: e.g. to improve the user experience of their native apps.

Competition in browser engines

The CMA considered that there are two key barriers to competition in browsers engines, being browser engine restriction on iOS and web compatibility.

The WebKit restriction

Apple has required all browsers on iOS to use WebKit as their browser engine. Browser vendors are also unable to make further adjustments to WebKit.

Apple has stated that this restriction is motivated by security and privacy concerns. But the CMA concluded that the evidence it has seen to date does not suggest that there are material differences in the security performance of WebKit and alternative browser engines.

The CMA says this restriction results in a lack of competition in browser engines on iOS, leaving Apple to determine the features a browser can offer on iOS.

The CMA reports that it has received submissions indicating that WebKit lags behind other browser engines in terms of feature support, general performance, and support for web apps.

Web compatibility

Web compatibility refers to a browser’s ability to properly access and display the content on a web page, which is primarily dependent on the browser engine. Web compatibility issues appear to be influenced by network effects, where the more users a browser has, the more likely online content providers will ensure their website is compatible with that browser engine. This compounds, making it more difficult for smaller browser engines to compete and for new browser engines to enter.

Competition in browsers

These barriers to competition in browser engines also limit competition in browsers. The impact is also exacerbated by pre-installation and default settings in browsers and Apple and Google restricting browsers’ access to certain features on iOS and Android.

The CMA found that pre-installed browsers have a significant impact on consumer behavior:

  • Safari is the pre-installed default browser on iOS mobile devices. Its share of supply in iOS mobile browsers is 93%.
  • Chrome comes pre-installed on most Android mobile devices and has a share of supply in Android mobile browsers of 75%.
  • Samsung Internet is pre-installed and set as default on 56% of Samsung Android mobile devices and has a share of supply in Android mobile browsers of 15%.

While users can change browser settings, the CMA concluded that based on user surveys, including a consumer survey commissioned by the ACCC, there is a strong tendency among consumers to stick with the pre-installed and default browsers. Ease of switching also plays an important role in mitigating the significance of pre-installation and default settings. A longer, more complex process for changing the default browser likely strengthens the impact of pre-set defaults.

The CMA also considered that there were limitations to the effectiveness of the Google Play store choice screen. These concerns included that the choice screen did not allow users to change the default browser setting at the time they decided to download an additional browser.

The CMA also received submissions from browser vendors reporting concerns in relation to access to APIs and other features on iOS and Android. Most submissions from browser vendors reported that there are features used by Safari which are not available to other mobile browsers on iOS devices. Some key examples of features not available to other mobile browsers include privacy and security features, browser extensions or add-ons exclusive to Safari, and device APIs for access to audio features and webcams.

The evidence received in relation to Google was more mixed. Some vendors submitted there are no major features available on Chrome which are not available on their own mobile browsers. Other browser vendors gave examples of interoperability being more restrictive for other browsers (e.g. Yandex submitted that Google can prevent other browsers from using technology which allows users to provide biometric authorization). The CMA’s conclusion is that overall, there seem to be fewer concerns about access to APIs on Android compared to iOS.

Where is the CMA heading?

The CMA’s conclusion is that Apple and Google have substantial and enduring market power in the supply of browsers and browser engines and that there are substantial barriers to entry of competitors.

The CMA is also concerned that Apple and Google may use their position in browsers to reinforce or strengthen their market position in other activities, including:

  • By limiting the functionality of web apps, Apple may seek to increase the take up of native apps, reinforcing its strong position in the distribution of native apps on iOS;
  • Google may use its market power in browser engines and browsers to reinforce its strong positions in the supply of ad inventory and ad tech services through its Privacy Sandbox Proposals;
  • Apple, as the sole steward of WebKit (the only permitted browser engine on iOS), may make open display advertising on iOS less attractive by limiting user tracking on browsers. This may decrease the competitive constraint of display advertising on search advertising, in turn reducing the viability of the web as a content distribution channel, and reinforcing Apple’s strong positions in the distribution of native apps on iOS; and

Through search agreements between Apple and Google, Apple receives significant revenues from Google Search traffic on Safari. The continued placement of Google Search as the default search engine on Safari also reinforces Google’s strong position in general search.


Read more: Mobile ecosystems