Google has begun testing a new feature on the iOS Gmail app: the ability to add non-Google e-mail accounts. The change would make the Gmail app more competitive with Apple's own Mail app and numerous other popular e-mail apps on iOS like Spark, Outlook, and Airmail.

The test was announced in a post from Gmail's official Twitter account:

Calling Gmail iOS users! Help us test a new feature - check your non-Google accounts from the official Gmail iOS app https://t.co/qVG44ygii2 pic.twitter.com/WZlUDSOtWX — Gmail (@gmail) October 17, 2017

If you try to sign up for the test, Google gives three criteria for eligibility: you must currently be using the Gmail iOS app, you must have an e-mail account that's not Gmail with which to test it, and you must be running iOS 10 or later on your device. Google hasn't said anything about when this feature could exit testing and go live to the public or even if it will. Some beta tests at Google have lasted weeks, others have gone on for years, and others never resulted in a publicly available feature or product.

On Google's competing Android mobile platform, the Gmail app is the default e-mail app, and it already supports third-party accounts. The app wouldn't be very useful as a default e-mail solution if it didn't. But iOS users who use Gmail accounts in addition to others—say, iCloud or Exchange—have needed to either use a non-Google app for Gmail, thereby potentially missing out on some Gmail features, or they've had to use two different e-mail apps.

The Gmail app is widely used on iOS; at the time of this writing, it holds the #1 spot in the App Store's most-downloaded productivity apps. Google also offers the Inbox app on iOS, a different interface for Gmail that was developed in part by former Sparrow product designer Jean-Marc Denis. It's a slightly different take on Gmail, but Inbox is not as popular at this time; it sits at the #94 spot in the same productivity app list. Inbox doesn't currently support non-Gmail e-mail accounts either.

In any case, Google's apps on iOS often lag behind their Android counterparts. In one of many examples, Google's iOS apps didn't support some of iOS 9's key features when Ars examined them six months after iOS 9's release. Google Assistant hit iOS months after its initial launch. If you want the latest and greatest from Google's services in the most seamless implementation possible, Google-backed phones like the new Pixel 2 are your best bet. But many, many people use Google services on their iPhones. Generally, it works pretty well, but changes like this that bring us closer to feature parity will be welcome.