One of the main reasons to use an in-app browser is when you click on an ad. Whether this is within Facebook, Instagram, or Twitter. They all use in-app browsers.
When you click on an ad you enter a site through a unique URL (query string), which is different per advertising platform.
How can in-app browsing impact pagespeed?
In general, entering a site through a query string comes with a slower Time to First Byte (TTFB). This may be due to the settings of the caching rules. But regardless of this, in-app browsers are not necessarily slower than a normal browser. As the data below shows.
The HTTP request method on the screenshot above shows "GET", which means that the site wasn't entered through an ad. The visitors that aren't using an in-app browser have a TTFB of 239 milliseconds, whereas the ones using one almost have the same. So safe to conclude there isn't any impact from the in-app browser, yet.
TTFB with a query string and an in-app browser
Let's have a look at the in-app browser experience when a visitor enters through a query string.
In this case, you can see that the TTFB has increased anyway, regardless of the use of an in-app browser. In addition, you can see that relative to the "GET" request method, users who end up on their in-app browser through a query string have a 10 times worse experience.
Different domain, different outcome?
To show that the problem does not only occur with the domain above we give you another example.
A similar increase in the TTFB occurs when someone enters through query string. However, add an in-app browser and you have an incredibly bad TTFB. Even though it's not 10 times as bad as the first example, it's still quite a deterioration.
Conclusion: What can I do to improve the in-app browser experience?
Unfortunately, we can't adjust the in-app browsers, so you can't do anything about it directly. In any case, we recommend to always check if your caching is set properly.
Because the TTFB is often difficult to improve, you should start looking at the other Core Web Vitals. By focusing on the other metrics, you can still ensure that your users have the best experience possible. Make sure your Largest Contentful Paint, Cumulative Layout Shift and First Input delay are performing well for your users.
