Learn about our WebView detection capabilities.
What is a WebView?
A WebView — sometimes called an “in-app browser” — lets apps embed a web page within the app itself. In other words: instead of opening a link using the user’s default browser, the link opens inside the host app (e.g., Facebook, Instagram, or many other mobile apps).
With a WebView, app users often have the choice: either open links inside the app, or in an external browser — meaning the same link could be experienced in different ways depending on how it’s opened.
Why Detecting WebView Matters
Detecting whether a visitor is viewing your site through a WebView — rather than a standard browser — is useful for a few reasons:
- Display and behavior may differ: In-app browsers (WebViews) sometimes render pages differently, or have quirks in how they handle navigation, cookies, or other browser features. By knowing your visitors are in a WebView, you can adjust or optimize to accommodate those differences.
- Better understanding of user access patterns: Knowing how users reach your site — via full browser or via in-app WebView — helps with analytics, performance tuning, UX decisions, and possibly tailoring content or prompts depending on context.
- Optimization and targeting: If you see a significant percentage of traffic coming from WebViews (for example, from social-media apps), you might choose to optimize for that case: e.g. simplify heavy JavaScript, defer non-critical resources, or adjust layout accordingly.
Detecting WebView matters for understanding user behavior and optimizing experiences (read more.)
How to Use 51Degrees to Detect WebView
If you’re using 51Degrees, detecting WebView is actually straightforward. Here’s how:
The 51Degrees IsWebApp property indicates whether the web page request came via a WebView (embedded in an app) rather than a standard browser.
Technically, this detection is often based on the HTTP headers (e.g., the User-Agent string). For example, many Android WebViews include "wv" in the user-agent to signal an in-app browsing context.
Below is an example of an Instagram version which has “wv” in the User-Agent and “Android WebView” in the Client Hints:
Mozilla/5.0 (Linux; Android 16; SM-S938U Build/BP2A.250605.031.A3; wv)
AppleWebKit/537.36 (KHTML, like Gecko)
Version/4.0
Chrome/142.0.7444.102 Mobile
Safari/537.36
Instagram 408.0.0.51.78
Android (36/16; 450dpi; 1080x2340; samsung; SM-S938U; pa3q; qcom; en_US; 832162521; IABMV/1)
sec-ch-ua: "Chromium";v="142", "Android WebView";v="142", "Not_A Brand";v="99"
sec-ch-ua-mobile: ?1
sec-ch-ua-platform: "Android"
sec-ch-ua-platform-version: "16"
sec-ch-ua-model: "SM-S938U"
To try it out simply paste a User-Agent string into the 51Degrees User-Agent tester (or headers into their HTTP header parser) to see how 51Degrees classifies the request. Alternatively, check the property dictionary for details on IsWebApp.
By utilizing this property, you can gain insight into how users reach your content — making it easier to tailor and optimize their experience accordingly.
What’s new — and what to watch out for
With the arrival of Android 16, there are important changes for WebView detection. In a recent 51Degrees blog post, we explain that Android 16 introduces User-Agent Reduction for WebView — a privacy-driven change that strips out much of the identifying information (device model, OS version, etc.) from the User-Agent string.
The implication? If your detection logic relies heavily on parsing User-Agent strings, you might start seeing degraded detection accuracy: more devices may show up as “Generic Android,” and platform/version detection could become unreliable.
To stay ahead: 51Degrees recommends supporting modern alternatives like Client Hint headers or combining WebView detection with richer data sources (especially for native apps), rather than relying only on the User-Agent.
Final thoughts — give it a go
If you haven’t already, try out 51Degrees’ tools: plug in a User-Agent (or full HTTP headers) into the User-Agent tester, and see whether IsWebApp returns true or false. With just that one property, you’ll immediately know whether a given request came via in-app WebView.
Don’t let in-app browsers obscure your analytics. Detect WebViews with 51Degrees and get real insights into user behavior right now. Start testing today and optimize your site before your next traffic spike hits!