Develop Reference

How to control who can install my app from play store?

I have an app that I want to be able to distribute to clients from other organisations. I don't want this app to be publicly visible on the play store, ideally the client would receive a link from me that would allow them to download the app from the play store.
I have had a bit of a search for this, so far I can only find 'Managed groups' (https://support.google.com/a/answer/2494992?hl=en) and 'closed tests' (https://support.google.com/googleplay/android-developer/answer/3131213?hl=en). A closed test looks to be along the lines of an ideal scenario, however the client would be aware that the app is in a testing phase, and may be able to do more with the app than intended for an end user. The managed groups also seem ideal, but they seem to be limited to my organisation, and when they talk about whitelisting that seems to be more whitelisting the apps on a user's device rather than whitelisting who can download the app.
Any help would be appreciated :)

To publish a private app within a client's organization (as a 3rd
party developer): If you’re an agency developer who wants to manage
the publishing flow on behalf of your client, or if you’ve built an
app for multiple organization clients and don't want the app to show
up in the public Play store, you can use your clients’ Organization
IDs to publish these apps directly to your client's organizations.
https://support.google.com/googleplay/android-developer/answer/6145139?hl=en

Does my android app need to use Google Play In-app Billing for in-app subscriptions?

I have a web app that works in conjunction with a locally installed desktop app.
Users have the option to upgrade to a premium membership for a monthly fee.
Both apps provide 100% of the functionality of my product(this is important for my question).
To widen my distribution I'm considering adding an android app.
Now, I know that Google generally forces android apps to use their in-app billing.
However, reading the developer terms I see this:
Developers offering products within another category of app downloaded
on Google Play must use Google Play In-app Billing as the method of
payment, except for the following cases: Payment is solely for
physical products
Payment is for digital content that may be consumed
outside of the app itself (e.g. songs that can be played on other
music players).
It seems like the bolded part applies to my product, since
it's not a game
the premium membership can be consumed entirely without the android app(using my desktop or web app)
Am I allowed to publish my android app to Google Play using my own payment processor or will google crack down on me?

You should be fine.
As long as the purchase isn't for something that can only be used inside the app, you're good. Since your purchase option applies across all platforms, you fall under that exception.
Of course, Google being Google, they could take down your app. However, you should just need to appeal that decision and talk to an actual person to get it sorted out.

Third party billing api in my google play app

I am making an android app to serve my progressive webapp content using webviews. I want to host my android app on the Google Play store. My webapp uses Stripe as the billing api to accept payments, start free trials, and apply discounts. However, after reading the Google Play terms of service, I am confused by the section here.
My webapp offers subscription based content. In other words, users purchase my subscriptions in order to access restricted content. My content definitely meets the requirements in Google Play's terms of service. On billing though, I'd really prefer to use Stripe as that's what I've been using up until now. The terms of service states on in app purchases that I must use Google's billing api as the only payment method for selling subscriptions.
I am confused for two reasons. The first is on this section of Google Play's documentation, they suggest using multiple billing methods in an app as a good practice, but this contradicts their terms of service. So then am I allowed to use Stripe on my android after all? The second is that I'm looking at other android apps on Google Play, such as Spotify. Spotify does not seem to use Google Play's billing api for purchasing subscriptions. So I'm trying to understand what makes Spotify exempt from this requirement.
I had two theories for why Spotify is exempt. The first is because they offer their content through multiple mediums. Website, Windows and macOS applications, iOS app, etc. Does this fact exempt Spotify due to this statement: "Payment is for digital content that may be consumed outside of the app itself (e.g. songs that can be played on other music players)". If so then my app falls under this category as well since a subscriber would be able to access my content on my website and iOS app in addition to my android app correct? My second theory was because I read here that Spotify carries out the in app billing process through an external Spotify webview. If this is the case, then my app would be accepted by Google Play if I do the same and handle the billing by serving an external webview?
So my question is given everything I've touched on above, would my android wrapped progressive webapp be accepted by the Google Play store?
Thanks in advance.

Short answer: If you are planning to rely purely on Google Play or some other marketplace to grow your business / userbase then build your app to use their payment system. If people visit your website from the web, tell them to download it from whatever marketplace.
Long answer: If you do some exploring you will notice there is no option to manage payments from some mobile apps only login / signup (free account). If you want to upgrade you are either redirected to a browser OR forced to use their online web app (because you end up googl-ing out of frustration). BUT Google is saying as of September 2021 there will be 0 links allowed to non-Google payment services for any app that is not exempt (physical goods / services). So unless Netflix is using big money loopholes to qualify as one of the exempt businesses they would need to remove the link to "manage subscription" in their account settings sometime September 2021 - or implement Google's payment system for their APK submitted to Google play store.
My advice: Keep it simple!!! Unless you are working with a budget or team, managing all of this on your own, and in production will be overwhelming, especially if you end up scaling. If you want to make a Google Play game or app then build it with Google in mind. Use Google Oauth, Google Adsense (free accounts), and use Google's payment system to upgrade users. As you grow, hire people to help you expand and maintain your project on new marketplaces.

Android app having a marketplace within the app

I've been going through a design for an app I wish to be making soon. My app will rely on user generated content. Is it possible to have users add an item to this in-app marketplace and recieve payments when other users buy from them directly using Google Wallet or PayPal? Is there a recommended way of implementing this type of feature?
Thanks in advance!

I am not aware of any recommended way to do this, however, doing this your app will likely not be allowed to be uploaded to the Google Play Store.
This would be against Google's Terms of Service as a developers apps is not allowed to make money through other means and other purchases that are made within the app have to go via the Google Play.

Payment gateways on iPhone & Android?

I'm looking for some advice on an app that I am hiring a developer to work on for me - its my first app and his first solo app, so I at least am still getting a feel for the ropes a bit.
My question lies in the area of in-app purchases. My app will use an in-app purchase system that will be used to purchase "credits" for lack of a better word. Each time a credit is purchased it will enable data stored in the app to be emailed to a particular email address.
I had originally thought it would be good to have an external web-based shopping cart to deal with it, but I understand there are APIs available to embed these shopping cart systems into the app. Additionally I also understand that any "digital consumables" that unlock features of the app are subject to the commission that iTunes/Android charge, does anyone have any initial thoughts on whether the ability to email would be included in this?
Many thanks in advance.

Savvas, that's not true at all ... AFAIK , in Android there's some exceptions you can read here: http://play.google.com/intl/en/about/developer-content-policy.html
Paid and Free Applications
App purchases: Developers charging for applications and downloads from Google Play must do so by using Google Play's payment system.
In-app purchases: Developers offering additional content, services or functionality within an application downloaded from Google Play must use Google Play's payment system as the method of payment, except:
where payment is primarily for physical goods or services (e.g. buying movie tickets; e.g. buying a publication where the price also includes a hard copy subscription);
or where payment is for digital content or goods that may be consumed outside of the application itself (e.g. buying songs that can be played on other music players)
So for example, for buying a coffee, you can use your own payment gateway.

I am pretty sure that both iPhone and Android agreements require you to use their own payment services for all in app purchases.
That means you can't roll your own paypal/visa/any other payment system and have your users use that if you plan on distributing the app via the Google Play Store or the App Store.
That being said, you can still roll out your own payment system if you distribute your app via other channels (for android you can have a look at the Amazon app store and other solutions. For the iPhone there is no official third party app store since Apple prohibits it. Cydia is an alternative app store that many people have though in their jailbroken phones)

Personally I am a big fan of Urban Airship. Works great on iOS and Android.